I firmly believe that the best counter to online platforms doing Bad Things is the ability of the userbase to migrate elsewhere. There's some cases where there really is only one game in town, ala Youtube, but for places that exist primarily for Posting or Messaging, there's always alternatives.
As the years go on I have less sympathy for people that are unwilling to spread out. It's one thing if an account somewhere has a games library or whatever attached to it, but things like Posting and Messaging only depend on other people being there to see it. For other people to be there... people have to be willing to be there. It's not really a chicken an egg problem because there's a simple solution: just go make a damn account. It's not like $Platform isn't giving you good reasons to want an alternative. Don't like having to remember your login? Use a password manager, hell most web browsers have one built in now. Don't like installing a bunch of stuff? Almost everything runs in a web browser now, it's just a tab. Don't like having more stuff open on your phone? Start out just using them at home, you don't need to be online in the literally-online-status-in-AIM sense all the time; people will be happy to chat with you when you're around. Worried about your "captive audience" being smaller on another Posting site than the one you're on now, and it will impact your business? Sorry, you're an utter fool not to diversify your online presence if it's an important part of you making money. Just want big number people to see your funny post and nothing else? Think about that one, that's homework for you.
I know that people want to just have everything in one place, but that's exactly what companies prey on now. It's bait. It's an ideal that you will be sold on, but you will never get. It will always be dangling in front of you, ever so close, and keep being pulled away further into the shit.
And you don't really have to leave the bad ones immediately, you just have to be elsewhere. That gives you, and importantly other people, the ability to use a better option. The more people have that option, the more people will choose it, then the more people have that option to choose, and the momentum grows. Then, when $Platform decides to make a Really Fucking Stupid Decision, it's a lot easier for people to go "actually fuck this I'll just delete my account and use this other option instead", which is the only thing that holds any weight as feedback. And when companies start realizing that these decisions will actually impact their metrics, they'll think twice about doing them.
All of that depends on people being willing to just use it in the first place, and honestly we both know that's trivial for most of us. There's so much shit in our lives that we have little to no agency over, it makes me so frustrated when people actively refuse to utilize it in situations where it's, frankly, very trivial to do so.
Signed, the person that took like 18 months to actually make a Revolt account. At least I got around to it eventually.