If you think about it though, it is actually easier to find replacement parts for 70s-90s systems because there is now a small industry around it as well as collectors and there was a differrnt culture around it.

Replacing things from 2000s-2010s systems is the bigger issues. They were all taken over by giant corpos with all repair parts, manuals, and software restricted and hidden in the name of "profit" and "protecting corporate IP" and now it is not profitable enough for them to spend resources keeping stock of old parts or driver installers, so into the trash they go, never to be able to be seen again, and reproducing them also is note challenging with increasing system complexity.