

You full on misunderstand the protocol. The .bsky.social subdomain does not denote what “instance” you are on. There are no instances on atproto. That user could be self hosting all there data and still use that subdomain. It’s not mutually exclusive. Atproto is far more atomic than AP.
It’s fairly easy to understand but you won’t really see it and that by design. The point is to make the underpinning so seamless that it feels like a centralized app. The proof of concept is Bluesky, but if you would like to see other services that are completely unaffiliated with Bluesky PBC than check out:
All of these and many more are being built along with infrasstucture plays from the like of Blacksky, Northsky, and Free our Feeds.