Part of that was the illusion of users that spam created, and part is the switch to paid relays makes the new user experience much worse.

I'd say the last part is that the way nostr is so fast, most clients are only fetching recent posts, you can easily lose track of people who you're subscribed to. With nos.social we're pulling from relays but storing locally in coredata so that we can highlight older posts (maybe like 1 day old) which are more relevant.