I think that some of that comes down to the fact nostr was conceived and is mainly being developed by people from the bitcoin community. And as a result, the largest group of people on nostr are bitcoiners. Doesn't help that many "normies" think that bitcoin=scam, so when those same "normies" join nostr some of the first things they see are about bitcoin so they nope the fuck out. It ends up being a chicken-and-egg problem caused by the fox having a field day in the henhouse. I think that if bitcoin haters can be convinced to not just join, but ignore bitcoin content altogether, we can get the diversification of content people want.