Lots of professional mining operations will actually undervolt the cards to get them to run more effeciently, decreasing electricity and cooling costs overall. Also there's less thermal stress due to them running constantly, so you don't get the physical stresses of fluctuation between hot/cold cycles.

Assuming the crypto bubble pops catastrophically and never recovers, yes we'll be left with a lot of worthless ASICs and GPUs, but also a ton of newly freed energy sources and chip manufacturing facilities, the development of which will have been funded or subsidized by the crypto speculative craze.

A world with more access to energy and cheaper silicon chips is probably necessary to address the immense challenges civilization is facing.

I have an exactly opposite experience - already got a second card from friends using them for mining when it was not good enough for them. Good price and both still working just fine for gaming. :)