Former Twitter users have a few options on where to go next. Ideally Mastodon/Fediverse. Blue Sky possibly. Likely Threads.
Users who go to Threads or Blue Sky will just make it Twitter 2, specifically Twitter from before Elon which I’ll be honest wasn’t a particularly great Twitter to begin with. (That isn’t to say the Fediverse is immune from the same fate, it just has some better protections against it.)
So option 1, Fediverse says “Fuck Threads”, Twitter 2 is born and it’s shitty for them. Fediverse gets a few new users, but mostly the Fediverse wonders why “everyone” is on Threads.
Option 2, Fediverse keeps an open dialogue with Threads. Threads users are more aware of the Fediverse. More Threads users actually migrate to the Fediverse. The Fediverse gets a wider range of users. If (when?) the Fediverse has to completely cut off Threads, the Fediverse will at least have more users, some of which will remain.
Another open question, does the Fediverse want former Twitter/Threads users?
Yes. More users, more thoughts, more opinions, more diversity, a better Fediverse. That isn’t to say I want shitheads. We can and should still ban shitheads.