Email and ActivityPub, by contrast, don't need any certification or lawyers etc for federation. Even though Google et al are working hard to enclose the Email commons by rejecting the bulk of non-cartel sourced email, it's a miracle it ever worked.
I can 100% see the benefit of having a semi-closed network, because spam and abuse are very real issues, and having a small group of people gatekeep makes the problem a lot easier to deal with. But it also shuts down innovation and competition.