Yes, I asked this a long time ago and the issue of 'success' came up. I think someone argued nostr was already a success because it functions, I don't think that seems right. Another version of success was that someone felt they personally had some benefit from Nostr. I also don't think that would count.
I think success wouldn't have to be being twitter-killer or anything. But it is sort of a matter of user numbers really. And I don't think it would have to be the same numbers as twitter or anything. I think I would say... Whatever user numbers matrix or substack has, wide(r)spread interest.
It's not an exact science lol.
I think eventually projects either do succeed or fail. Like that twitter alt called Ello (or any number of them). We can pretty much safely say that did not succeed, right? 🤔