Tbh, birdsite exodus is not that huge at the moment. It seems like it's going to peak at 800k users per week. With 10% of active users, we have a whole one-two months before the count of new users will be equal to old ones.
Admins have time to react, users have opportunity to tell newbies about the culture on fair grounds, founders have a moment to adjust their development strategy for larger userbase. With 1 mil of new users per day we wouldn't have all that.
~~Praise the lord~~ Thank Musk, birdsite hasn't shut down completely yet