In addition to the airlines not wanting to take on the security job again, I'm not so sure that the general public wants the airlines to take it back. Remember how no one ever watched the monitors? Or how spotty screening seemed to be... I was in a small airport once when the rent-a-cop did a complete dump out of my carry on because he saw something "suspicious".

IMHO, the biggest benefit of creating the TSA is that it creates one "company" we can all be angry with rather than the haphazzard ways it was implemented previously. I actually don't have any grievances with the TSA as a whole... they are doing exactly what they've been told to do and funded for. Problem is that there's no end to the madness.