> 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.