I recall being in my early teens, when I went to create my (first) Facebook account. I mentioned it to my dad. He explicitly told me that whatever I did on Facebook would go to their servers, that whatever reached their servers was theirs, and that they would do whatever they wanted with that data regardless of whether you agreed to it or not. The whole reason I gave up and made an account was because my friends had already given the app their contact list, and the service already had my phone number.
From day one I've treated online services like amoral, dangerous animals, and so far nothing these organizations have done has especially shocked me, though I have been impressed or surprised on occasion. My mantra is generally 'if I or the NSA could imagine it, private industry will attempt it'.
I still get a lot of value out of my Facebook account. Facebook pages are a gateway to niche interest groups, social trends, and the political fringes that would otherwise be inaccessible to outsiders. Seeing the ads Facebook puts in my feed helps me to calibrate my mental model of how I'm being observed, who's sharing data with who, and how online services perceive me (I typically use ad-block, and only occasionally close it to check my ads).
If I want to contact someone I've only met in passing, keep up with family and political bubbles, or do a bit of background investigation, Facebook's there for me.
Accessing the service requires a bit of a faustian bargain. But by the time I joined, the country had already made it on my behalf, so I opted to reap the benefits of that bargain rather than just being social collateral.
Facebook could scare me off the way Google Search did - by sanitizing its content feed to the degree Google's sanitized its search. But I'd still use Messenger, and any other useful service they come up with.
But otherwise it'd have to become obsolete in the same way as MySpace.