"If we divide up states into homogeneous sections, pretty soon every neighborhood will be its own state."
Some science fiction writers have hypothesized about this for a while. Technology is trending towards empowering ever smaller groups to manage their affairs quite effectively, and enabling those groups to rapidly snap together with other groups on an as-needed basis. It isn't that hard to look out 50-100 years hence and ask what all these massive centralized governments are really doing for us that couldn't be done by much finer-grained bands of smaller ones. (Don't think something like every county fully a nation in the modern sense, think something more like the relation of states to the federal government, and counties doing things like perhaps buying into pre-existing health care plans or something, across a wide array of such issues.) There are days when the US government's current trend toward centralization seems downright anachronistic to me.
I recall one science fiction story in Analog where after significant advances in nanotechnology, the minimum self-sustaining unit of civilization became a single house. It was literally possible to seal off a suburban house plot and it could survive solely on the incoming solar energy and the technologies it had. After the homeowner got in some trouble with the local law enforcement, he has the bright idea of simply seceding from the nation, though various legal handwavery and appeals to the ancient question of the social contract. It was one of those interesting, thought-provoking stories that at least made me think. Yes, I am well aware of the other tradeoffs involved and how important defense and preventing the tragedy of the commons is, the point is not that this is obviously a good idea, the point is that it is not unthinkable that we may indeed be trending towards smaller polities in the future. The outcome of the battle between centralization and decentralization haven't been written yet.