I would imagine this is only true to a certain point.

Like, I would not be surprised if there were issues trying to run an AGP or PCI video card.

There's probably a sweet spot where some hardware is old enough to have had all the major bugs worked out, but not so old that nobody bothers developing and testing it anymore.

I'm sorry but this is all but true. I've a 13700K and a 4090 and it's more reliable than 2 of my old hardware machines..this is slowly becoming a myth unfortunately as new versions of either DEs or desktop protocol (s) are slowly deprecating tons of stuff..