Unless and until we come up with a different economic model for social media, we'll always have Facebook (or Twitter, or whatever successor toxic social media site comes next).
Plenty of people here on HN have argued that the real problem is centralization, and I agree. Take whatever specific issue one might have with FB -- let's say disinformation, for instance. We have all these debates about censorship vs free speech vs accountability etc. But in fact, if FB wasn't the behemoth it is, much of this would be moot. In a world where there were _only_ smaller, more niche social media sites, fears around things like online radicalization would be much less, and any well-founded suspicions of actual criminal conspiracies would lend themselves to much more targeted warrant-backed investigations rather than privacy-destroying giant electronic dragnets. And if this example doesn't work for you, pick another one and think through how a world of smaller, less influential sites would change what you see as the problem with social media.
But you can't brute force your way to that world -- that's pushing against a very strong current. So long as the economic model is to create a large, targetable advertising market, you're going to have very strong incentives for centralization and invasion of privacy.
Contrast this with non-digital social hubs -- say, a pub. People come for the socialization, but the actual product being sold is food and drink. Social space becomes a side effect, one that complements and enhances the business model (a pub with a reputation as a good place to meet friends gets more business), but the business model isn't data-mining your audience.
I think a social media network that focused on extending offline hubs into social spaces, where the economic model is attracting an audience to gather and chat and then _selling them something_, would mitigate the incentives to centralization and invasion of privacy. We need to tie social media to the selling of actual products; users need to be customers, not the actual product.