I have watched countless videos of people opening up old video game consoles. Talking ones up to year 2000 or so.
They never touch a radiator or mention using some kind of technique or measure to get rid of the static electricity in their hands/bodies.
But this is super important when you open up a computer.
Why is this? Is there something about old consoles that make them immune from this threat?
Your claim of "super important when you open up a computer" is a bit strong and I counter that it's not. This is not to say that it's not to be considered at all, but is part of a risk assessment which operates on a continuum.
High-humidity environments cause static build-up to self-discharge. The user's habitual choice of clothing and footwear can mean that they don't generate it and/or it easily dispels again. The flip side is of course that low-humidity environments and certain clothing fibres can result in dangerous (to chips) high voltages.
Different logic families and even devices also have different levels of robustness against static electricity. Early CMOS devices, especially some which omit protection diodes, were infamous for failing easily due to static electricity. However, a lot of older computer systems are based on TTL and/or NMOS devices which can take quite a bit more abuse.
Also, once in-circuit, other components can provide a lower-resistance discharge path and thus add an extra level of protection. There's also an element of good luck involved, since once one is handling an entire board, it's less likely that one will touch that one weak spot which would be killed by static.
So, people who are not susceptible to static build-up quickly learn that they can safely poke around in old systems without taking anti-static precautions. I'm one of them: I've always lived in a maritime climate and static just isn't a thing which happens here.
Touching a radiator won't help a bit, unless the device under operation is also bolted to the radiator.
The point is that your body and preferably the whole environment is at same potential with the device under operation so there are no static discharges with the device.
If you touch a radiator, you will be at the same potential as the radiator before you collect more static charges, but the device that is not connected to radiator may have several kilovolts compared to the radiator and you.
The proper way is of course to have an ESD safe environment. It will prevent ESD events by equalizing charges that have already built up and will also prevent charges from building up. For example grounded ESD mat and grounded wrist strap keep you and your environment and the device at same potential.
Old technology can be slightly more resilient to ESD as the chip structures are larger and can handle the ESD properly. Much older technology was worse because even if the chip structures were larger, the ESD protection technology did not protect much (the early 4000 CMOS series chip as an example are much more sensitive to ESD than later 74 series TTL or 74 series CMOS chips).
It might also be that they have proper precautions in place, and maybe they just don't mention it it videos if it is not the point of the video. Sort of like when you start disassembling a car engine, you don't necessarily need to specifically mention to turn off and make sure the engine is not running before you start disassembling it.
The opened consoles may already broken or faulty so it does not matter. Or they just don't know or care about ESD. The problem is also dependent on geography. If you live in a humid environment with no carpet on the floor, that is much safer than living in a dry environment with a carpet.
It's hard to give an answer without any of the situation (videos) you refer to provided, as there are many ways to avoid ESD damage. The most important: don't wear plastic/gummy soles and clothing and handle slowly with care. Also, most consumer devices, like consoles, aren't as sensitive. Next, while older technology is more prone to ESD, especially old CMOS, more modern - and that starts already in the 1980s, are well protected against most ESD situations. So when handled with minimal care, chances for damage are very slim.
They never touch a radiator or mention using some kind of technique or measure to get rid of the static electricity in their hands/bodies.
But this is super important when you open up a computer.
No, it isn't. Today even less than back in the days. As Justme already pointed out, Touching a radiator only matters if that radiator is at the same (ground) potential as the device you're working with.
Is there something about old consoles that make them immune from this threat?
Kinda. Most devices aren't connected to a common ground at all. This is especially true for home computers and consoles. Essentially all devices that operate from a two prong mains plug (*1) do not carry a common ground with any radiator or whatsoever.
A device not connected to any ground potential, to which the handler is as well connected, can have any potential. It doesn't matter. It could be at 15,000 Volts against ground and still work fine. That's why power lines can hang nicely between poles without shorting. It's the same reasons why birds can sit on high power transmission likes without starting to glow.
So unless a differential potential is created, nothing will happen.
ESD or ElectroStatic discharge is when two potentials equalize - ever felt that spark when touching a door handle after going over some plastic carpet? Jup, that's ESD. Notable here, it happens despite the door handle being not grounded at all (*3). Why? Because it's all about equalizing potentials, not connecting to a certain potential.
And that's the most important reason why usually and most the time nothing happens when people handle old electronics in videos. They carry the device, put it up a table, open it etc.pp. During all these actions the potential between the electronics on the inside and the handler do equalize. Slowly and in a harmless way.
Which is the second point there: Damage is not caused by voltage (otherwise above birds would again be fried) but by current. Thus, if equalisation happens slowly, next to no current flows, but electrostatic buildup is removed. That's also why ESD bags aren't good conductors but bad insulators (*4)
So the task is to (slowly) equalize potential and keep it that way. This can be done by careful handling, supported by tools. That's where, for example discharging mats, wristbands and connections in-between come into play.
Whatever needs to be handled gets placed on the mat - still within transport packaging. The handler wears a wrist band connected to the man, and after unpacking the device as well gets wired up.
And that's why my workplace setup consists of two quite classic Knürr Elicon tables:
(Picture taken from their Brochure)
No, mine are just basic grey ones, without the integrated add-ons, but more shelves (*5). Not cheap but all worth it. All components are grounded, the tables are covered in discharging surface. All connected to a common ground, including my chairs. Essentially no chance to build up a potential.
Whenever handling a device it gets put onto the table and sit there for some time after connecting to the tables potential. There is essentially no chance to build up a potential.
Having said all of this, in most real world situation it will work fine without additional tools, by simply acting sensible.
*1 - There are certain configuration where it still could be, but these are rather rare and confined to certain states/regions/networks.
*2 - Still have it. Please don't ask for details or pictures.
*3 - Dry wood is a rather acceptable insulator.
*4 - Meaning they have a moderate to high resistance, allowing a potential to discharge slowly, so whatever is inside gets slowly adapted to whatever is outside with next to no current flow, thus no damage.
*5 - Again no, there are neither in such a nice room, but a dark attic, nor are they clean. Rather cluttered with electronic waste, documentation and tools :))
Old (and new) video game consoles are just as susceptible to static electricity as old (and new) computers. If you're not grounded, you can kill your Coleco if you start messing around under the hood.
The only thing that might be a difference is that some video game consoles are designed to be a touch more resilient to static electricity when in their closed and sealed state. I don't recall friends ever rubbing their fingers against the cartridge or joystick connectors because these tended to be a bit more shielded physically and/or electrically (i.e. cartridge connectors are recessed and sometimes even behind doors). Maybe some designs were a little extra careful and designed the circuits for these exposed connectors to be a little closer to a grounding path? I can't say for sure.
But that being said, once you open up the device all bets are off since consumers weren't expected to open them up in the first place.
As a side note, I can say that I did accidentally blow out the Bluetooth module on a WiiU GamePad because of static electricity. Somewhere between the couch, carpet, and power cord I ended up generating enough that when I plugged the device back into the charging cable there was a spark and the Bluetooth module stopped working beyond a few inches after that. Fortunately, it was an easy fix to replace the module :-)
Unsurprisingly, the same physics apply to old electronics as well as new. :)
Some components are more easily damaged than others but in general nothing is safe from the tens of thousands of volts an unlucky ESD discharge can introduce.
Insulated gate devices (e.g. CMOS ICs, MOSFET transistors) are very ESD sensitive as it is easy to punch through the gate oxide. You are much more likely to damage those devices than TTL, but modern devices often has some level of ESD protection diodes built in, lowering the risk. That doesn't imply any kind of immunity, though.
So, yes, it remains good practice to have yourself and the thing you are working on at the same potential, also on old electronics. Often you get lucky, of course, and nothing happens even if you don't. Other times, something may happen even if it is not immediately visible (degrading the device).
(Incidentally, the key is to be at the same potential - it only helps touching a radiator if the thing you are going to touch afterwards is also at that potential, fx from being grounded)
Early (1970s) semiconductors often lacked the type of ESD protection that is ubiquitous with current components, so I would argue that precautions are more important when working with older devices. In terms of real-world situations I would maintain contact with the chassis of the device; grounding yourself on a radiator and then walking back to your workplace could well result in more static charge than if you had remained still.
Back in the 1990's when I worked at Philips in Cambridge UK, during the walk from my desk to the EPROM eraser, about 300ft, I used my car keys to discharge static every 20ft or so to avoid a painful ESD strike. In my lab today, I've never had a static shock. It's all down to carpets, humidity and shoes. The problem is, an ESD shock that you cannot feel is sufficient to kill a chip. Unless a circuit has specific ESD protection on pins, you will risk damaging a chip.
Back in those Philips days, we had a production failure issue that we found was caused by people on the shop floor pulling off an adhesive label on an IC on the PCB. The tear force on a plastic label was enough to kill the chip. We just moved where the label was placed.
In my lab, wood floors and wood desk, I have no issues and have taken no precautions. So it just depends. Take ESD precaution approach as required by your environment and your concerns on the risk of what happens if you create an early life failure problem (ESD damage does not always occur immediately)
One of my suppliers notes that, although the power electronics they produce are robust and ESD safe, they managed to reduce the number of pre-shipment failures from 1 in 10,000 to 1 in 500,000 by introducing ESD protection measures.
Modern digital computers are fairly ESD safe, but also worth 100s of dollars, not cents per item. The precautions you take depend not just on the risk, but also on cost, re-stocking time, and other measures of value.
