It's a bit of a paradigm shift. Particularly if you haven't already had a paradigm shift with bitcoin.
I'm also guessing that many people see no reason to leave the big tech platforms (or venture outside if them), even if they don't like them, because that's where their friends are. Or because they play the algo game and have invested a lot into the rat race.
Like banks, Big Social is sticky. Takes a lot to cause someone to look elsewhere. Beyond that, there are so many *alternatives* that if you have not had the paradigm shift and cannot see how Nostr is so much more than social media, it probably seems like *just another alt social platform* in an ever growing sea of options.