On the "AI is just a bubble" side we have: AI is not as good as claimed therefore its impact is not as significant as advertised - ergo it is a passing fad & market caps are inflated.
On the "AI is legit" side we have the counter: AI is as at least nearly as good as claimed and/or has potential to be - ergo the hype is warranted & it's here to stay & market caps are warranted.
I'm in the third camp: impact is not related to merit, and AI is impactful in not-necessarily-positive ways that are societally transformative & will reach far outside any bubble & persist. Probably to a more significant degree even than predicted. And I think this extends far beyond the impact of purely economic knock-ons as seen with some latent impacts of blockchain speculation.
Given that third thesis I don't think the market caps are significantly inflated (beyond any other comparable market caps outside AI): investment is not merit based, it's impact based.