It's a little different to federated networks like GNU Social/Mastadon since the data and the relay are separate. You can post the same data to multiple relays and read from many relays simultaneously. Meaning you aren't tied to picking a single relay with network effects, and although a big relay going offline might cause temporary chaos, it's fairly easy for new ones to be set up and added to clients, without having to explicitly move things like accounts and so on.