Let me present my take on why the federated alternatives struggle to replace X:

Twitter didn't succeed because it was a particularly good solution - it really isn't. It succeeded purely on the back of the network effect.

When every open-source alternative simply copies the existing restrictions without adding any unique value, why would users switch to an equally flawed version where none of the accounts they actually want to follow are?

People did fly to Bluesky. Some accounts there have 1 million followers.

Bluesky got the decentralisation UX right.

My take is that Bluesky got the network effects right, with hyping and gradual release and careful curation of who seeded the network and that is - IMO - the important thing they got right.

What do you mean by 'the fediverse that missed the Twitter alternative'? I thought Mastodon is the Twitter alternative. Sorry; I didn't het it.

Bluesky became that, while Mastodon had months of head start.

I guess I don't get why all of these don't target better user experience goals - one login / trust plane and full distribution for decentralization.

The way I'd look at it is more like Bitcoin where everyone can decide how much compute to give to the pool to verify people or posts and maybe everyone shares chunks of the whole pie with copies like freenet.

Maybe I'm (likely) too dumb to get why this isn't what things in the fediverse is but they all are an awful experience and having so many hosts makes critical mass non existent so I can't be bothered to participate.