@poVoq I used to think that treating the server as a cityish thing made best sense. But cities are dense, they are used for everything including many things we often don't think about (see Jacobs, etc.). The mapping doesn't work very well, except perhaps for people who are very much in one community rather than overlapping ones.
The ATProto approach is credible exit and all the properties that make servers into commodities. It means that you have better flexibility in dealing with infra.