I think credit card details, phone numbers, or some Apple ID are part of the verification process.
So a previously blocked customer might be blocked on that basis.
The other thing Twitter can do is develop some software process which looks for these impersonation accounts, highlights them and perhaps automatically locks them.
Basically Twitter now is where Tesla was in 2008, lots of work to be done, and success isn't guaranteed. But using logic and reason rather than emotion, I give Elon and Twitter a fighting chance, because computer software isn't that hard, and incremental improvement always works.