Yeah, majority (if not all) practically used servers are currently operated by a single organization. I'm sure it wasn't complicated to block the entire service entirely in some countries (compared to Nostr for example).
Similar issue with Bluesky: something that was supposed to be decentralized became unavailable for everyone due to outages and DDoS. It's hard to imagine this will happen to Nostr anytime soon. Global outages don't happen there because a single organization deployed a buggy relay release on every single server at the same time or because a drone crashed some data center: according to relay discovery events, there are currently more than 2k relays operated already, definitely not by a single human in a single building.