Small isolated relays that develop unique culture and mores is how I always perceived nostr when more mature.
There has been a subtle centralizing Twitter like effect where everyone is connected and sharing a unified sub global over a dozen or so relays.
I really do see familial, friend, private & topical relays taking shape. Switching between relays to interact more or even using a single client with a single npub on a single relay.
The point is not to fomo but rather create your own worlds.