> GPUs do not last forever, either. I've read here, and heard from others, that they aren't even living up to their 5 year depreciation schedules under production load, closer to 2-3 years

People said this about GPUs during the crypto mining craze and were wrong back then too. While I can’t speak for the entire industry I can say my personal experience follows any normal intuition over solid state electronics.

Some early failures in the bathtub curve, and then you start seeing fans, heat paste, and board capacitors fail far before you start seeing any chip failures at scale.

Sure you can abuse anything you want to burn it out, but I doubt that’s what’s happening inside these facilities.