There are hardly any alternative networks? GSM/3g/4g are illegal to run on an ad-hoc basis most everywhere. Which leaves cabled networks (which are generally not legal to set up as metro/internets -- or even link freely between different buildings if you need to cross community owned land) and wireless mesh-networks.
I think both are interesting, but I don't see them forming a global interconnected network capable of delivering symmetric gigabit to 10 billion people (not that the Internet of today does that either -- yet).
I suppose local 802.11-whatever community networks might be connected in metro-/internets with high-bandwidth point-to-point links -- but it seems likely that they'd end up connected to the Internet -- perhaps on the ipv6 Internet.
Either way, hopefully internet access will continue to evolve like a utility, like electricity and water.
Interference with 'official' networks, besides that spectrum use requires a license in just about every country except for some very specific low power unlicensed segments of the spectrum.
