> Does the free ad model just not pay anymore, or is the selling user data model just that much more lucrative that they would rather no user at all if they aren't logged in?

Traffic from google is probably in the process of collapsing, so these sites are trying to capture all the users they can as registered users before it's gone completely.

And yes, the free ad model is probably in the process of dying, the information that was once given away for free in return for looking at ads is now more valuable sold to llm's who will have the eyeballs going forward.

This will presumably make many on this site happy, since for many years an ad supported open web was consistently railed against.