Yeah BlueSky has a lot of control over the network but I wouldn't say that email isn't federated because Google controls a lot of the email network.
I was pleasantly surprised to see that Bluesky released a personal data server implementation openly. But now that they did, it looks like the AT protocol network minimally qualifies as federated.
I wouldn't really compare Bluesky to Mastodon. Ultimately, the Bluesky team still has control over what's allowed on the app and what's allowed on the network until third parties launch their own AppViews and relays.
Yeah BlueSky has a lot of control over the network but I wouldn't say that email isn't federated because Google controls a lot of the email network.
I was pleasantly surprised to see that Bluesky released a personal data server implementation openly. But now that they did, it looks like the AT protocol network minimally qualifies as federated.