Yeah your argument is a valid one I think, but as long as Nostr is decentralised , it will naturally begin to be more respresentative of it's user base.
This stuff is early days , it's a decentralised social layer that uses public/private keypairs so naturally all the Bitcoiners are on it like flies on shite.
Piece by piece, as more and more people hop on the bus, it'll become a melting pot.