Nextgen and Privatizing Air Traffic Control

Trump was pushing these two ideas on TV yesterday.  Right now air traffic control (ATC) has been run by the FAA and paid for thru appropriations of federal tax money.  Trump (and others) want to set up a private or semi private company to run ATC and be funded by levying  fees on the airlines who use ATC.  The airline industry is in favor, as is the ATC union.   The issue really comes down to funding.  Right now, every time Congress gets its panties in a twist, the FAA funding bill doesn't get passed, and when it finally does pass, it leaves out funding for capital improvements, new radars, new control towers, new computers, Next Gen and such.   With a private company funded from fees, the cash flow is steady and predictable, every one's paycheck comes thru on time, and  capital improvements can be made, especially long term multi year projects.   The down side is the private company can hire more people, buy more equipment and just raise the fees to pay for it all.   They have a monopoly, and they will exploit it to grow. 
    The capital improvement under consideration is "Next Gen" an expensive plan to force every airplane in the country (and out of the country) to buy an pricey GPS receiver/transponder.  This gadget uses the GPS part to find the plane's location, speed and course, and when interrogated by a ground transponder would transmit the plane's ID and location back to the ground to update the ATC displays in control towers.  Transponders start at a couple of K for a light plane model, and a lot more for an airliner grade model.  The advantage of Next Gen is greater accuracy, say 10 feet of so, as compared to  5 miles or so for today's ground radar.  Which is said to allow controllers to fly planes closer together, allowing more air traffic in the same amount of airspace. 
   Maybe.  But it relies on vulnerable technology.  The GPS signal from satellites is quite weak and could be jammed in wartime.  The NextGen GPS/transponder is complicated and should it fail the aircraft disappears off ATC display screens.  And there is plenty of airspace for flying from place to place.  The congestion occurs around airports.  We only have 50 odd airports in the whole country and each one can only handle one operation (takeoff or landing) a minute.  There is plenty of airspace inbetween airports for all the planes now flying and all the planes that will be flying in the future.
   We should not do Next Gen.  Too expensive, too vulnerable, and we don't get anything for spending all that money.