I still think onboarding people to Nostr is about onboarding them to a Nostr Store of apps. It would be great if I could just reference them to the ecosystem instead of a single app.

I'm becoming convinced that won't happen, not in the first minute in any case Most people will come to nostr for some concrete reason, not because someone told them nostr is cool so they want to browse what to use. Once they understand the nature of nostr, know what the nsec is and so on, they are ready to explore what else is interesting - there is where the store appears