Huge DCs and Power Generation might be useful, long-lasting infrastructure, however, the racks full of GPUs and TPUs will depreciate rather quickly.

I think this is a bit overblown.

In the event of a crash, the current generation of cards will still be just fine for a wide variety of ai/ml tasks. The main problem is that we'll have more than we know what to do with if someone has to sell of their million card mega cluster...