I don't see how that can work at all.
My initial reaction is to agree with you, but an optimist's response would probably be something like, "Is that a reason to not even try?"
And as soon as I start to think that way, I consider just -- as you suggest -- managing to get cities assembled into their own intranets (not even necessarily connected with one another). Would that not be some type of victory?
And who's to say that, if that were to happen, some corporation or conglomeration of non-profits wouldn't come along and donate "dark fibre/fiber" to connect some of those cities with each other for the good of human-kind?
Or that after setting up city intranets, someone discovers a way to send data using pulsed streams of neutrinos, and that that technology is found to be economically viable enough that it can be used for connecting at least the largest of those city intranets?
Who can predict the future? And seriously ... is there a reason to not even try?