Looking at https://upload.wikimedia.org/wikipedia/commons/c/c1/Commodore-64-1541-Floppy-Drive-04.jpg I started thinking the following:
There are too many chips in that drive. It is crying out for a cost-reduced version. (The price of the 1541, was one of the short list of complaints people had about the Commodore 64.)
The 1541 actually contains a 6502 CPU.
But that CPU is only about 3500 transistors. By the mid-80s, at least as far as chip area goes, it would have been easy to merge it into another chip. In this case also legally no problem for Commodore, as they owned MOS Technology.
Now that I think about it, I don't remember CPU cores ever being merged into other chips, not in those days. It happens nowadays, of course, but I don't remember hearing about it happening in the 80s.
Was any CPU core ever merged into another chip, in the 8-bit era?