Twitter's mMAUs (monthly Monetizable Active Users) stands at 450 million. If they pay $8 per month, that gives Elon $3.6B per month. It will take 13 months to make $44B - the purchase price QED. Elon Musk is a genius.
From $20 and then dropped to $8, and it is facing a lot of backlash from users. I think if he really applies that fee then people won't pay to stay, they're willing to quit this social network and find another. Social networking is not a monopoly, it is facing stiff competition and we have a lot of free social networks. Although twitter is the most popular social network, that does not mean it cannot be replaced.
One of the persons who are against the monetization of Twitter subscribers and even though the $8 monthly fee for verified Twitter user accounts may look small to those who have a lot of marketing and endorsements to promote on twitter.
The majority of other Twitter verified users may simply look for an alternative to Twitter especially if their account is not used for commercial purposes and does not yield any income monthly.
Even if this work, it will only lead to more centralization of Twitter, and in time to come other rules may be added to the Twitter policy.