That's kind of true. You obviously know the reasons why it should be true, but consider also (the "kind of" part) the fact that there's stuff like mastodon, lik

That's kind of true. You obviously know the reasons why it should be true, but consider also (the "kind of" part) the fact that there's stuff like mastodon, like small hobbyist forums, unpopular telegram groups & channels that don't sell ads, imageboards with a couple hundreds of users. They appear because people (the users, not so much the owners) need them. And they are (at least sometimes) loosing to FB/reddit/twitter, because there's at least something (even if that "something" is the network effect) that these Companies are better at providing. Which means, that even if they only want to be companies, they (unfortunately for all) indeed are the "social media" in some sense. Sometimes even borderline with "essential infrastructure".