Source? Anecdotally, GPUs sourced from cryptomining were absolutely fine MTBF-wise. Zero apparent issues of wear-and-tear or any shortened lifecycle.

My bellybutton fluff, uninformed opinion is that heat cycling and effective cooling are probably a much more limiting factor.

If you are running a gpu at 60C for months at a time, but never idling it (crypto use case), I would actually hazard a guess that it is better than cycling it with intermittent workloads due to thermal expansion.

That of course presupposes effective, consistent cooling.

Anecdotally, I killed two out of two that I was hobby-mining on for a couple of years. They certainly didn't sound like they would work forever.