Spitballing

There is no clear path to the trillion dollars today. By IPOing, the owners (who have a good idea of where it's going) can exchange their ticket to the trillion for cash today.

Seems like a bad deal unless you know the ticket won't get called. Then you've just made bank.

And you might have noticed some form of hype around AI these last few years - arguably this could be to make the trillion dollar seem more realistic and therefore making the owners more money when selling their ticket to it.