> Any people running Linux on some rare old hardware care to share why?

It's called retro-computing and it's simply a hobby. You could also ask why people are fixing, maintaining and driving around with cars that are decades old.

It's also a very good method to learn everything about kernel development and maintenance. On x86, there are enough people looking at and working on the code, so you will have a hard time to find things for improvment.

The m68k port, on the other hand, has many places where you can help with improving the code and therefore get your feet wet with kernel development.