I can see some research institutes snapping up some cheap just-out-of-warranty Blackwell 200s and running them until they die. I've got proximity to that, so it's visible to me... I can't see a lot of other use cases. I imagine they're going to be similarly niche.
Most HPC systems use commodity hardware, just a lot of it in cluster. The most recent nodes we have on the system I help to manage are equipped with either ECC DDR5 5600 or 6000, depending on which batch they came in.
Zitron's analysis definitely agrees with you about who will be hurt if/when this all crashes... and I can't see how he's wrong about OpenAI's commitments vs their income. I can't see how any of it go to this point unless the market operation selected for people who were irresponsible (but lets face it, that's not exactly a new idea).