You can run your own relay with your own rules. You could run a relay only for gardening, and block all Bitcoin posts. You could run a local relay that only takes notes from approved posters that you know personally. The freedom of Nostr allows you to have whatever you want on your own relay. This combined with the outbox model being widely implemented will make sure your notes get to people who want them.

I think the key is making running your own relay easier, that way it doesn't matter what other relay operators do.