People expect free when they are told to, and expect to pay when told that.

Nostr will grow organically by friends bringing friends, walleting them up, introducing the ease and power of small micropayments and in effect sidestepping Global.

I'm not too concerned.

I also expect spam killing to get better. A script that auto publishes spam npubs to all the relays, that then parse it and if that npub joins (take their money, why not), then blocks their write.