You seem to be treating Pubky as some sort of more general idea, while in fact they are two completely disjoint things. Nostr assumes don’t trust, verify by default but can be loosened. With Pubky, each application needs to invent its own way of verifying and it is discouraged by the design. Nostr relays are inherently simpler than Pubky homeservers. Nostr can also propagate data through a variety of methods, while Pubky makes it hard to not rely on homeservers.