The positives you listed are features of most social networks, not just Facebook. If Facebook disappeared overnight, another platform(s), hopefully more ethical, would quickly take over its role, and it could be a net positive for the world.
That seems very optimistic to me. Ethically, Facebook is the perfect exemplar of an internet-oriented company. No better, perhaps, but no worse either because it's such a low bar. It seems at least as likely that any replacement would turn out to be even scummier, simply because it would absolutely have to hire from the same talent pool and would have had even less time to figure out what all the ethical dangers are.
But it's simply not going to happen, so this is all moot.
