You can own your own data very easily in many ways, either by posting to your own relay or having a local copy of it, there's a couple of clients that have that functionality AND more importantly there's the incentives, because of the NIP architecture, and the whole Nostr architecture in general, for relays to just be data servers.

It's all open, we can create everything. The game is open and forces data to just be data, and clients to just be clients. There can't be data silos on Nostr basically.

All of this combined turns the incentive around. It's the people and the posts that matter. If people have good content, relays will always want to have that content.

This combined means in pratice that we have all the opportunities to own the data, than ever before.