I just cannot imagine monetization on Nostr yet. Most people aren't used to pay, to store their data. You can reason as much as you want, they will still prefer the 0-cost alternative.

And with the number of "premium" relays growing, many users will find themselves locked-out.

Can't we come-up with some sort of network funding? Where ultimately ~5% of the users, pay for 100% of the infastructure? A bucket, that's split among relay / proxy and storage operators, based on the capacity they provide (and process).

Sourcehut does something like this.