Decentralization and erasure: Blacksky, Bluesky, and the ATmosphere

There's been a lot of discussion about whether or not Bluesky and the ATmosphere (the ecosystem using the AT protocol) are decentralized. Blacksky runs three feed generators, a moderation service, and a work-in-progress personal data store (PDS) as well as providing a starter pack. And the vision for Blacksky "extends beyond any single platform".

That sounds pretty decentralized to me!

But as far as I can tell, nobody else in the discussion is talking about Blacksky as an actually-existing example of decentralization. What's with that?