It is not criminally under explored, there are tons of work done on that side of the equation, almost none leveraged by Nostr so far, for example I haven't seen anyone working with Automerge or engaging with the ink and switch people, most likely because all that ecosystem has little to no intersection with Bitcoin.

But these are not mutually exclusive concepts and giving up on open data stores is a step back from the old days of Email and WebDav... why take steps back?