As exciting as Nostr is this sounds like it has the same fatal flaw as every other platform...
When it gets popular, people will aggregate around a handful of (or network of) relays where most content will be published, then governments, NGOs and tankies will co-opt and monopolize these to impose their orthodoxy and control information. As it was with reddit, twitter, and more recently lemmy.
Maybe I don't quite fully understand relays yet, but I don't see how this won't happen eventually.