I agree that the focus on decentralization is a distraction, but Mastodon and Bluesky are perfectly fine alternatives that are just as easy to use as Twitter.

The fact that they have not succeeded in attracting a critical mass of Twitter users to jump ship is all the evidence we need to show that network effects are real, and overcoming them is really hard.

Also, I don't think most people on Twitter "want" to move. I think most people don't care about Musk or his politics, at least not enough to care about leaving his social media site. (And a significant chunk of people in the US, at least, likely are in Musk's camp anyway.)