The shift is that the content itself now has tangible value.
So far it's been the attention of the users that has been monetized, primarily via advertising.
But now the content generated by the users has value as input into AI training sets. And AI companies are scrambling to gather as much as they can as rapidly as they can.
The data itself, not the attention of the users, is what is now being harvested.
The companies hosting the data are right to intervene, there's no reason to allow incredibly well-funded AI organizations hoover it all up for free.
Where it's going wrong is how the social companies are intervening. Their goal is correct, their methods are not.