There is a bit of a huge big fat alt coming through tho in the shape of BlueSky which will eat a lot of that movement maybe? Even tho it may suffer the same problems as what theyre leaving, that will be a concern for another day. The primary concern is content chasing.
I think what nostr has going for it tho, in an optimistic twist to this thought lol... Is it might come up with a killer app outside of this twitter format. Maybe something like the highlighter or a marketplace or gambling or whatever it is. Which may in turn bring people to this aspect of nostr I'm currently typing in. ¯\_(ツ)_/¯