I think the OP hit the nail on the head.
TSA will never go away. If there are no attacks, it "proves" TSA is doing its job. If there is an attack, it "proves" we need to give even more power and liberties to the TSA.
Privatization, with strict government oversight, would be ideal, as a private company might actually return some semblance of "customer service" to the screening process, an idea that TSA management has no familiarity with.