As a couple of posters have already pointed out, the cost of stringing cable to locations in sparsely populated areas climbs toward the stratosphere. Which, in and of itself, is a deterrent to profit oriented business (read as cable monopolies).
Then, to expect the government to throw in huge sums of money to 'rectify' the situation is simply inviting the telco/cableco monopoly to an all they can eat feast..
Those of you who are familiar with the Telecommunications Act of 1996, may recall that federal subsidies were on the table to carry out exactly what is being proposed. And the monopolists just sucked up the cash, and left the rural areas wanting.
In the 1930's the Rural Electrification Act made it possible for isolated communities to bring electricity to areas that lacked electricity. Now, if the Feds want to perform the exact same thing with broadband, then I am for it, but, keep the telcos out of it. They had their chance.
Rural Electrification Act: https://en.wikipedia.org/wiki/Rural_Electrification_Act