Honestly, couldn't really care if twitter did this. After all, what's the #1 reason other social media sites can't ever seem to succeed? Because twatter already has everyone. If they give everyone the boot, it just opens up the doors for "us" to make a new, better one, with blackjack and hookers.
Also, so they boot everyone but their own kind and movie companies to advertise? So they only advertise to those who already think like them? If they want to waste their money preaching to the choir they can go right ahead.
…and even when it becomes a "perfect" safe space/echo chamber, we've all seen how quickly they turn on each other. Once they get rid of all the "conservatives" then they'll get bored and go after the "whites" or the "old" or those who used the wrong gender pronoun, or…
…and eventually the whole thing just shuts down.
Either way, I really can't be bothered to care.