It's still too complicated for the layperson to have to navigate. Anything beyond "I have one login at one site that everyone else has" is too much for most.
Well, shareholders, employees and advertisers, wanted it to make money on the users. Even if only 5% users remain, that's still better than the current interest rates after investment fund's fees.
Facebook/Instagram users wanted to check it out, because why not, creating an account was just a couple clicks.
Everyone else... they didn't, and from the looks of it, they still don't.
Zuck wanted it, and literally nobody else. They're going to need to implement ActivityPub just so every blue checkmark on earth can launch their own social network where they are the only users.