Nostr is literally websockets and json, things that make up the web already.

Relays are just databases, things that make up applications already.

Just because you don't know how to scale them doesn't make them not scalable, and as far as I know there's only one developer actually working on scaling it  nostr:npub1yxprsscnjw2e6myxz73mmzvnqw5kvzd5ffjya9ecjypc5l0gvgksh8qud4

Scale will come quickly ones its made a priority.