Even if TPU’s weren’t all that useful, they still own the data centers and can upgrade equipment, or not. They paid for the hardware out of their large pile of cash, so it’s not debt overhang.

Another issue is loss of revenue. Google cloud revenue is currently 15% of their total, so still not that much. The stock market is counting on it continuing to increase, though.

If the stock market crashes, Google’s stock price will go down too, and that could be a very good time to buy, much like it was in 2008. There’s been a spectacular increase since then, the best investment I ever made. (Repeating that is unlikely, though.)

Meanwhile OpenAI et al dumping GPUs while everyone else is doing the same will get pennies on the dollar. It's exactly the opposite to what you describe.

I hope that comes to pass, because I'll be ready to scoop up cheap GPUs and servers.

If it gets to the point where this hardware is useless (I doubt it), yes Google will have it sitting there. But it will have cost Google less to build that hardware than any of the companies who built on Nvidia.