I know Paul Graham is not someone you generally want to take any advice from, but it's hard to not see truth in this:

By 1998, Yahoo was the beneficiary of a de facto Ponzi scheme. Investors were excited about the Internet. One reason they were excited was Yahoo's revenue growth. So they invested in new Internet startups. The startups then used the money to buy ads on Yahoo to get traffic. Which caused yet more revenue growth for Yahoo, and further convinced investors the Internet was worth investing in.

And it certainly seems like it all applies if you replace "the Internet" with "AI" and "Yahoo" with "OpenAI".