It will end up being de facto EEE, the same way it’s become functionally impossible to run your own email server. Sure you technically can, but the handful of big players block everything else and make it impossible to actually email anyone.
It’ll be like that on the fediverse. Big companies like this will dominate the space, refuse to federate with most others except the big players, and people will realize that unless you only want a mastodon instance with like 20 people on it, it won’t be worth the trouble.