Related question: Is the AI bubble smaller or larger than the dot-com bubble?
Of course, there are listed companies with significant AI investments. But I'd argue their valuations are driven by their existing/conventional/ad-driven scale, not their AI arms.
Whether or not they're overvalued remains to be seen. The era of cheap money seems (?) to be coming to an end, so it will be an interesting few years.
It was the IPOs that drove the boom (and subsequent bust). Public investors falling over themselves wanting to get in on the "next big thing". Older generation companies were never going to deliver the kind of quick return multiples that characterized the boom (though as we saw, the enthusiasm certainly jacked up their share prices too, but by and large they managed to ride out the storm).