People need food, so people will pay for food. Because people will pay for food, other people will grow the food. Believe it or not, this would still happen without rural subsidies.
As rusty points out, consolidating districts could eliminate unnecessary administration without actually closing schools. Regardless, the worst case scenario is that a few underpopulated schools close, and the kids have to travel further to other schools or parents choose to homeschool. This would not be the first inconvenience of rural living. The truth is, rural living sucks in a great many ways. It also has some advantages. Again, there's money to be made there in ag and energy, so if that's what you want to do then good for you. But stop expecting the rest of us to pay for your lifestyle.
(How's that for a winning message? I should run for governor.)