It’s a funny one because it’s not like it ever really took off.
Architectures like m68k are also probably pretty dead, but there’s a ton of these chips out there in embedded or retro kit and you can probably find one to test on if you need it.
There are also newer M68K cores designed by retro-enthusiasts to run in FPGA, either as emulator or as CPU accelerator in vintage computers.
An example, the Apollo 68080: http://apollo-computer.com/apollo68080.php
The Amiga crowd is probably the main reason m68k is still supported at all. It's a neat architecture but basically all of the hardware is out of production and has specifications which are untenable for a modern Linux system (<50 MHz, <256 MB RAM).
