I think very cheap paid relays are an option. The admission is like a CAPTCHA that adds considerable friction for spammers.
If we had easy to host paid relay software we could create a market to drive prices down and also lead to censorship resistance.
Or require an actual CAPTCHA before posting to a relay. Maybe there's some way of providing proof of CAPTCHA too so you only have to solve it once and you can replay it on many relays.
there's no such a way and captchas can be bypassed with AI
Are you sure? I think you can construct them in such a way that they're at least extremely hard to solve by automated means.
I am intrigued by a pay per note posted model, like what keychat.io is trying with their stamps model for messaging. Ecash makes it feasible.
