Shutting down twitter, rumble, and substack would be a massacre for independent media right now. Elon could make an offer that couldn't be refused on the other two, and turn on the censorship harder than Facebook.
The right-wing free speech heel turn is always the same: when you censor, you're trying to prevent the free expression of ideas, when we censor, we're trying to prevent the "support" of terrorism. Lèse-majesté is always around the corner.
But yeah, if there is a truly distributed system, that had facilities and incentives which support and even promote diverse interactions, that'd be even better.
I firmly believe his posture with twitter has been because 1) it's a fun place for him and it was obviously a money losing purchase* so he might as well have that fun, and 2) his level of censorship is something that he can use to negotiate with government over contracts or regulation.
He might even really believe in free speech, but a conceptual belief in free speech doesn't mean he'll feel obligated to personally provide it if he can make a dollar denying it. His speech will remain free no matter what happens, he's a rich guy.
-----
* (not unlike say the Guardian, the New Republic, Mother Jones, the Intercept, or the Atlantic, or the WaPo, aparently, and probably CNN and MSNBC at this point. They're not for making money.)
But I'm with you on the potential problems and would rather have a system that was immune to such issues. What i'm really arguing against is people who saw the previous regime as correct and just, and are looking to recreate their echo-chamber somewhere else.
Part of what it will take to create a healthy town-center, that is much better than X, is for more people to speak up for ideals of diversity and tolerance. And to fight against the very loud and angry segment of people who see censorship and authoritarian control as good things, as long as they're working in their own favor.