pupa on Nostr: If spam cannot be solved for free here on nostr, then nostr's model will be similar ...

If spam cannot be solved for free here on nostr, then nostr's model will be similar to that of Twitter (although much cheaper and affordable): pay a few paid relays or you get spam and scammers everywhere.
I'm saying this while being convinced that relays must be paid, they route and store our data and that has a cost, simple as that, and I rather pay a few thousands sats than get ads and god knows what happens to my data.
I'd love to get some stats that help determine if paid relays are billing us enough to be sustainable over the long term...