At $20, or $5 or even $1 this could have some of the effects Elon is looking for, especially dumping bots. At the same time, it seems like it would have others he’s not, like paying for “free speech,” cutting out folks with tight budgets -- and yes, there are people who need that $20 for their bills...
Seems like it would turn away more legit users than the improvements it generates would attract. But that’s just a guess, they’d have metrics on that before they acted.
It is an interesting proposal though, if legit.