Today I saw a reply from nostr:npub180cvv07tjdrrgpa0j7j7tmnyl2yr6yr7l8j4s3evf6u64th6gkwsyjh6w6 and I couldn't see the note he is replying to, until I manually took the event key and relay mentioned in the reply tags and queried that relay myself.

If the original poster migrated relays since (think forum comments from a year back) then there would be no way to find that note again.

Even worse nostr:npub12262qa4uhw7u8gdwlgmntqtv7aye8vdcmvszkqwgs0zchel6mz7s6cgrkj himself can't actually migrate while ensuring all his notes moved, because Nostr events aren't In an authenticated data structure, full sync is impossible to verify.

While this works fine for what Nostr was invented for, to replace the general usecase of the Web, we need to a proper sovereign DNS equivalent like #pkarr, and we need user's data to be durable, not just host agnostic.

And yes ed25519 + key delegation is a must, and they will absolutely pay for their complexity by providing long lasting identity, and anyone who says this is not practical is bearish Bitcoin because Bitcoin doesn't mean shit for anyone who can't keep a key cold.