This wreck will be studied in marketing courses for decades and decades. It's just amazing how badly this was played. Musk bought the company, immediately went to war against his biggest customers[1], then demanded that they all then pay him for a previously-free feature that... didn't actually do anything for the people who had it[2]. What did he think was going to happen?

And the hilarious thing is that they're rolling it back now, by adding the blue check mark manually to "important" (or just popular) accounts that would be most subject to impersonation, essentially using it to mark "Twitter knows who this person is" as a signal to everyone else. Which is... exactly what the feature was for originally.

[1] Journalists, pundits and havers-of-opinions.

[2] At its core, the check mark is a feature for the rest of us, so we don't get scammed by reading imposter accounts.