A great idea to be sure, but I think the capital costs at the beginning would be really tough. If they are going to make their own data network they at least need to buy spectrum, which is insanely expensive (high millions to low billions).
The requirement to buy spectrum is what has kept the lid on radio network innovation. With appropriate technology, spectrum would not need to be ransomed by the agency that the incumbents own. We've seen rapid progress at 2.4 and 5 ghz, the unlicensed (i.e. free) nature of which may be the single greatest legacy of the microwave oven. If only the FCC would quit dragging its feet on white spaces and similar radio tech possibilities, and do what it promised to do a decade ago, we'd soon see similar progress at frequencies that accommodate longer ranges. This would create serious competitors to the broadband monopolists.
You've seen rapid progress at 2.4gh and 5ghz because the FCC keeps power limits really low. If I were allowed to blast my signal all over my town, we'd all be interfering with each other left and right.
