Gregory's Server
This is the thing. Sociability is *about people*. If your people are in an architecturally worse place or a place with a weirder business model, you may still choose to go be with them.
The alternative social internet has to get this and build itself to be really liveable and interesting for more people OR accept that it's going to be niche.
Building for niche, then scolding people who don't get it is understandable, but it's missing a workable theory of change.
I write a lot about the things that the fediverse can offer that you can't get anywhere else—humane governance according to local norms, especially. I think those things are extremely good, and there are lots of people and groups who stand to benefit from those things.
But you still have to build things people like using, or they will leave/not join, and then the social part goes poof.