I like the free market aspect of Nostr relays.
-Any given relay is likely to eventually purge, and thus render notes ephemeral. Not necessarily a bad thing.
-People can pay relays for assurances of...
Also, one can do decisions about spamminess of any note. If most relays are wanting to carry a note it must be less spammy, whereas if nobody wants to hodl, touch it it must be spammy. Fuzzy logic.