Arguably, there is already an incentive for airports to opt out of using the TSA: doing so allows them to provide better customer service which is a competitive advantage. In theory airports are not required to use the TSA - http://www.nytimes.com/2012/03/16/us/airports-with-new-law-a...
I agree in theory, but the last airport that tried to do that got threatened by the feds with being shutdown, and the FAA said that they would shut down the airspace around it. So they _can_ kick out the TSA, but that would mean that they would have to shutter the doors.