Have you actually seen this happen? Whenever I've seen HOA-provided internet access, it's just been a group buy from Comcast or AT&T or whoever. The end result in this case is that everyone has the same basic access they'd have if they subscribed individually. They just don't pay a separate bill and they get a cheaper rate (and they can't decline it).
Having a building administer its own network with a single IP shared by the building sounds terrible. What happens if you want to run a server? Or open up a port that some program needs to listen on? I can't imagine a building having network technicians competent enough to make this situation work well.
