Running a server isn't practical for average people. It's also nothing new, people could do since the dawn of the Internet, they don't need a Fediverse for that.
> You can freely move between the islands.
I can freely move between Facebook and Twitter too. Again, not seeing what the Fediverse is doing here for me. The Fediverse does not prevent walled gardens, the federation is an optional server-provided feature that can be switched off any time they want. You can't even move your data from one server to the other unless both servers cooperate.
And Lemmy specifically isn't even GDPR compliant, there is no way to export my comments in the UI. There are also other huge issues such as message-ids being tied to the server, so you can't even resolve a URL from one server with another (something Usenet did better 40 years ago, which is why I can still find old post today).
> Mastodon achieves a similar
If Mastodon decides to run ads and enshittify, it's just like Twitter again. There is nothing to prevent that, outside of being small and unpopular.
> Decentralization obviously doesn't on its own protect anything from the governments, but it helps.
I am not worried about the government, I am worried about overzealous mods and server admins, who are already running rampant on the Fediverse and the Fediverse provides no infrastructure to help me here. That's an area where I much prefer Twitter and Co., they are pretty hands-off with moderation as long as you don't violate the law. On the Fediverse thought-policing is getting sold as a feature.