But, let's be frank here: They monetize you and me, us, the users because 1 they can and, 2, they have to.
Yes, they have to.
Imagine they provided access to their platforms for free. How would the shareholders (your retirement funds included) respond when less profit was made?
You see, we view them as public utilities, as a shared park or public garden or nice riverside picnic area, but they are not anything like that at all. They are companies that have a responsibility to the paying user, that is to the advertisers who want to track you as a viewer, to know if/how much their ads work.
The closest thing to a "public utility" on the internet to this day is email, good old SMTP/IMAP email. It's open, everybody who's not yet on Hotmail's or Gmail's spam-list can use it, and you can even develop an app for it yourself if you so wish.
The closest thing to a social open protocol is: the fedi-verse on Mastodon or the relay-based Nostr system. You don't want to be the product of a mega corp? Try these open platforms instead...