Stock prices don't have to crash. They can just stagnate while profits catch up and multiples compress.
Debt binges, on the other hand, tend to go bust with a bang. But after the recent private-credit scare, the AI build-out has been predominantly financed with stock. (I think.)
I believe that's been concentrated at the hyperscaler layer, and subsided when the aforementioned private-credit scare reared its head. (I haven't heard a big datacenter debt deal announced in a while. Though of course that doesn't mean they aren't being done.)
Is there is historical evidence for that? As someone who used to follow Jeremy Grantham a lot (he considered himself a "bubble historian"), IIRC every bubble he studied always mean reverted, and it usually (maybe always, can't remember) overshot on the downside during the correction.
This really depends on how we're defining these things. Let's call a stock-market bubble a period of elevated multiples. That can mean revert by prices decreasing while earnings stay constant or by prices staying constant and earnings rising. (Alternatively, both earnings and multiples can rise and fall.)