[_jss]

You'd have to change more regulations, because airports don't close when ATC closes, it regresses to an untowered airport environment (and related airspace designation).

ATC is there to provide specific services that increase safety and throughput (mostly by sequencing and separation).

If you did this with the ruling class, they'd likely pass regulations that would benefit themselves disproportionately and hurt general aviation (the small little Cessnas flying around). There is already a bunch of problems with privatized ATC, don't make it worse.