Altman's main interest is Altman. ChatGPT will be acquihired, most people will be let go, the brand will become a shadow of its former self, and Altman will emerge with a major payday and no obvious dent in his self-made reputation as a leading AGIthinkfluenceretc.
I don't think ads are that easy, because the hard part of ads isn't taking money and serving up ad slop, it's providing convincing tracking and analytics.
As soon as ad slop appears a lot of customers will run - not all, but enough to make monetisation problematic.