This is not about that.

It's just about being able to publish "this is my latest profile", "these are my latest posts", so your "true state" isn't tied to a single relay. it makes nostr far more censorship resistant. imagine the 10 largest relays ban alex jones. But alex jones publishes a hash of his latest stuff in an OP_RETURN. So you know you don't have the latest sync. Your client can then keep an eye out for new relays, by looking in your followers profiles, connecting and requesting alex's content until it discovers the correct relay.

As long as one person you follow has a relay in common, you can find the content, know you are up to date.

Good clients should suggest relay changes to match your follower set.

Censorship resistance is, as usual, the hardest thing and the most important thing.

Algorithm support is important too! But it can go 2 ways: Client and Server. FWICT there are no NIP proposals around how to implement feed organization and conversation discovery algorithms.