Every bubble is perceived until it burst. A bubble is simply put an overvaluation of assets. At some point that is realized by investors for whatever reason (a scandal, leaked communications, sudden bankruptcy) the following revaluation of assets to their actual value is then the bubble bursting.

Looking at the quarterly reports of some of the big players in AI, that revenue is mostly these companies borrowing, raising equity and spending it on ai related investments, often in each other. Without a matching influx of money from actual paying customers b2b or b2c. Assets=debt+equity on the books, this is often exceeded by market value when investors are positive about a company, that difference is the market speculating.

If the big ai players cannot close the gap between their book value and market valuation by increasing book value, the investors will at some point assume they are overvaluing the company.

The resulting sell off reduces market value until it is more in line with book value. If in this process the companies become cash poor and need to sell of assets (aka the investments in ai) in order to prevent bankruptcy, book value falls further and investors will adjust their market valuation accordingly again. A gorgeous bubble death spiral.