I don't know, I think more and more people are waking up to the fact that if we want to avoid the mess we're in now, we've got to start paying for things.
Once you've hit 1 billion users, at that point you've pretty much become an institution. You've never marketed it as being free forever so everyone knows the score so they're more prepared. Sure some people will leave but I think the majority would stay unless there was some seriously good competition. I think most minimum wage workers will see one hour of work out of an entire year as reasonable, it's a lot less than most other tech subscriptions. And to anyone earning above minimum wage it's begins to become practically nothing. There would be moaning for sure, but compared to other utilities it's an absolute bargain.
I think social media needs to start being seen as a boring utility which it really is rather than the never ending frothy hype machine of myspace/facebook/instagram/snapchat/tiktok/future platform which only really serves the VCs and investors who earn money. I think there's a lot of people out there who don't want to have to keep on learning new platforms endlessly, they just want something that everyone they know is on, that works well, is simple, and that doesn't track them or bombard them with ads. I think this is part of the reason why LinkedIn has been so successful in that it is quite boring and doesn't change much.
In a way there should be the frothy hype machine apps for the youth and then the one boring adult platform for when you grow up and stop being an idiot and don't mind hanging out with your parents again. Facebook kind of was this platform, but then most people abandoned it other than the elderly (e.g the completely tech illiterate) because of how manipulative it got.
The other alternative, which I think a lot of people would hate but might actually solve the problem, would be for Apple to finally give it a shot and release something. They're already a heavily moderated walled garden and verification could easily be proven through Apple Wallet. They could easily plug things into the existing apps, e.g an instagram photo feed in the photos app, facebook style groups in the messages app, profile page integration into the contacts app etc. Maybe one new standalone "Community" app which has two tabs: an "everything" feed from all your contacts and then a Discover tab for popular posts nearby in your town. A focus on your actual family, friends and community rather than videos of randos dancing a million miles away that add nothing to your life. I think they may end up with some regulatory heat on them if they succeeded though; they would end up being extraordinarily powerful.