This is true, but do we have a need for random airports in sparse parts of the country that require government subsidies?

There's more of a need to not have planes hit each other and cover areas with wreckage.

I can just imagine the hilarity if air-space was sold off to the highest bidder and then some of the smaller airports may decide to host advertising blimps in their share of the airspace and then charge plane companies extra to navigate around them.