The airlines never asked for TSA. In fact the airlines would prefer doing their own screening like the old days. And 'crony capitalism?' That makes no sense.
The airlines asked for both retrospective and prospective relief from liability for the actual past (retrospective) and potential future (prospective) security failures in the wake of 9/11.
Nationalization of the security function was the mechanism for the prospective portion of that relief; since they no longer controlled the function, they would no longer be liable for any failures.
Now, they would have preferred immunity from liability while controlling the function, but even their allies in Washington couldn't sell that open-ended a handout publicly. But TSA security theater made adequate political cover for the real purpose.
