I mean, look at this shit. I wouldn't buy any of these companies right now, though I think Apple, Microsoft, Broadcom, Google, and Netflix, will be OK even when AI crashes. They have real businesses that make money, AI is just a side quest for them. They'll fall, but not crash.
But, Nvidia? Tesla? Huge exposure to AI and no way to justify their valuations if absolutely absurd SciFi things don't come to pass.