I know, right? It seems so dumb that it's hard to believe. They're free to the right sort of people:

Applicants need to be notable in fields such as government, entertainment, sports or political activism, and they need to abide by Twitter's rules including a ban on the glorification of violence. [0]

Which probably means one can get a checkmark if one pays the right PR firm, who kick back to the right twitter middle manager, but twitter shareholders don't get a cut. Twitter has completely ignored an obvious source of revenue for its entire existence.

[0] https://www.nbcnews.com/tech/social-media/twitter-verificati...