> there is no single component of the system that does not have a open/alternative option for exit.

Users can move their follows, followers and posts to zeppelin.social fron BlueSky transparently?

Now you can of course debate on what "decenttalized" means, but in a social network easy migration between servers is the crucial feature that would allow the decentralized network to emerge.

Edit. Does the network actually work over at zeppelin.social alone if Bluesky servers go down?

Yes, all of those social graph relationships are hinged off a permanent identifier (DID) and everything comes along when accounts migrate PDS instances. Folks can use zeppelin.social from any PDS instance. The DID PLC directory is currently hosted by Bluesky, but the directory can be forked, and did:web identifiers can be used as an alternative (and several independence-minded folks in the network do so).

Migration between servers is so seamless that is causes confusion and doubt that the protocol even supports migration, because there is basically zero in-app visibility of which users are on which server.

Yes, the network continues to work on zeppelin.social if Bluesky servers are down.

> Now you can of course debate on what "decenttalized" means, but in a social network easy migration between servers is the crucial feature that would allow the decentralized network to emerge.

I totally agree. However, a lot of people in the fediverse/ActivityPub world apparently (?) disagree, seeing as your domain is tightly coupled to your server, i.e. no name portability. Seems like a wild oversight to me, and getting massive instances like matrix.org and mastadon.social seems like an inevitable consequence.

Lack of name portability implies greater risk when choosing a server. Greater risk when choosing a server means choosing comparatively less risky servers. Choosing comparatively less risky servers means choosing more well-known servers. Thus you have the GMail-ification of the fediverse.

> Users can move their follows, followers and posts to zeppelin.social fron BlueSky transparently?

Yes, even if Bluesky was down (as long as they have a backup) which is not the case for ActivityPub.