Interesting, I agree that the probability of the majority of users using potentially heavily censored default relays is high. However, I think that we both do agree that NOSTR does have a clear advantage over fediverse by allowing users to completely own their identities? Which in turn makes circumventing relay/server censorship way easier and does not require users to start over completely from scratch if they get banned. That seals the deal for me personally.
Discussion
If you have valuable content, people will try to find you. And certainly free minded people will continue to run uncensored aggregator relays.
Which btw you can do on your own relay. Just publish to every relay that you can find.