We already see "paid relays" and relays that filter certain content, even as small as nostr is today. I think the end state, if it manages to really catch on, is going to be as "oligarchical" as mastodon or other federated networks today - just via relays instead of via homeservers.
A step in the right direction for sure! But I don't feel like Nostr is the final target that nature is shooting for here.
The solution to bad relays is to just use different relays. Changing your relays is just a matter of publishing a new 10002 relay list, and optionally copying over your old notes (or reseeding them from local backups).
+1, user owning the ID is a step in the right direction compared to "homeserver" owning the right key and makes this possible.
That said - maybe (total hypothetical) the reason one relay becomes really big is because a lot of people think it provides really good service, and maybe it's difficult to convince the majority of the network to route around it. This would create a similar problem to what we see in more well established federated chat networks.
A step in the right direction for sure! But I don't feel like Nostr is the final target that nature is shooting for here.