There's no need as compared to Bitcoin nostr doesn't really "need" consensus. So in theory you can do whatever you want anyways. NIPs just help with interoperability between clients which makes total sense.

Yeah, in that sense... there's a group of people running Monero wallets plugged into Nostr

I know nothing but here goes. I assume it is open source right? Then it should be forkable or at least reproducible. So anybody should be able to create their own #nostr, independent of fiatjaf right - right? *leia meme* However this nostr we are using, by forking/reproducing we would probably not get the content and need to start from scratch. And as long as we are using this nostr, fiatjaf can probably change the code? I dunno. 🤷🏻‍♂️

Nostr is a description of how things work. Relay and client devs build software that works to fit this description. That is a protocol. It's always changing and evolving, guided by not only fiatjaf, but also the devs of clients and relays, a collaborative and combative process.

So open in the sense that anybody can build on it while the protocol can also be built on by the proprietor? Built from both sides? Thanks, it makes more sense. I have never really tried to think about how it works.

Yes, except their is no proprietor really. Permissionless. Anyone can make an npub. Anybody can code whatever client they want. Anyone can run a relay.