Why can't FB charge a minimal subscription fee? For 2-3 bucks a year, wouldn't they keep the vast majority of users and simultaneously remove their dependence on shadowy advertisement dollars?
But there is more revenue than just that. FB allows advertisers to reach specific audiences, and even create lookalikes, so overall, there will be a %age of the users seeing more ads than me, potentially personalized for them, and average revenue per user would be higher.
[1] https://s21.q4cdn.com/399680738/files/doc_financials/2019/q3...
Also, the numbers you posted include all the inventory - facebook news feed, ads on the side right on desktop, instagram, messenger ads, stories ads, instant articles, and even the ad network. According to facebook (read somewhere) 70% of their ads are on the ad network.
This is why you can’t pay to get a version of The NY Times that has no ads.
https://www.cnbc.com/2017/11/02/facebooks-revenue-topped-5-p...