Put aside the obliteration of stock value and job loss. What would be lost, and how hard would it be for folks to replace it with something else?
I imagine it would be all the talk for a hot few days. There'd be a hustle and a bustle as folks tried to entice their friends to other services. There'd be a land grab to recreate network effect lock in. There'd be talk even among normies to avoid it.
It'd be glorious, I tell you.
And three weeks later, there'd be a winner that got most of the exodus. A few people standing around looking for a chair in a 21st century version of duck-duck-goose.
A year later, things would be largely the same. Just as abusive. Serfs to different lords. No one would miss Meta.