The Atari 5200, released in 1982, had four controller ports, an unusual feature which as far as I know had never been seen before, and would not be seen again until the late nineties.
The 1983 revision of the machine, reverted to only two controller ports.
We don't usually observe later hardware removing features. What was the reason for it in this case? I can think of several possibilities.
Perhaps most obvious: the videogame crash was in full swing; maybe they weren't thinking strategically any more; maybe they were just in a panic trying to do anything that would save a couple of dollars (how much did the extra controller ports add in manufacturing cost, anyway?) in an attempt to stave off bankruptcy.
Or maybe their game designers were not coming up with games that would accommodate four simultaneous players.
Or maybe their market research had started indicating, rightly or wrongly, that their customers weren't interested in four-player games. (That doesn't sound right. Game consoles tend to go in the living room, or sometimes in college dorm rooms or suchlike, where getting three or four players together would be a natural thing to do.)
Or the machine didn't have enough computing power to handle four players at a time? (That doesn't sound right, but then I haven't actually tried designing four player games to run on that hardware.)
Or something else that I haven't thought of?