What made everybody move from a corporate social media platform to another corporate social media platform instead of the fediverse?
After all, the Fediverse and Activitypub is much more mature than Bluesky and the copycat AT protocol or Threads and … whatever they use.
Bluesky is a lot easier to use fresh out of the box. Even though their feature set is quite similar, Mastadon has a clunky and confusing UI, and still lacks a native iPad app-- instead they offer a poorly ported iPhone app.
That’s led to more people using Bluesky, and it snowballs from there.