I agree with OP's title on the social side of the problem, not the technical one. If we allow them to destroy the Fediverse, then it was already lost to begin with. It's not a matter of technology, it's a matter of whether the key people are able to keep it out of the corporate control in the long run. If they can't, then it was all just a matter of time.
EDIT: I don't imply it's a particularly useful thought. It might help with coping though if it would ever happen. Let's enjoy it while it lasts and hope for the best!