Why would a federated RSS feed be 'the beginning of the end' for decentralized app datastore tech (think: decentralized version of Firebase)? Those two things are wildly different, so I'm not understanding your comment - it's like saying 'the automobile was the beginning of the end for the airplane'.
It took Jack's focus to Nostr. Has nothing to do with the tech
I was more asking why you think Nostr possibly succeeding in the future means that we don't need other technologies. These two technologies, analogically are basically RSS : Firebase :: Nostr :: DWeb Nodes, so it's not like you can build every type of app on RSS, you eventually need datastores. Why do you view this as some battle where there can only be one winner? Did cars make planes unnecessary for you?