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.
It's too early to jump to conclusions about Twitter's pretty tough monthly revenue of $44 billion over 13 months going into Elon's pocket. This value is the accumulation of the overall revenue earned from the monetization of the social media company, excluding advertising. while twitter must pay employees, operations, taxes, directors, and others. so I can say $44 billion is not Elon Musk's net income.
The Tesla CEO only owns 9.2% of his total stake in Twitter, so it took him several years to recover his capital from his shareholding in Twitter.