Quick question. How many bombs have made it on planes in spite of the new, post 9/11 security theater and how many have been stopped? That's right, not one, ONE, report of a bomb being found/stopped by security. Passengers on the other hand, they all but kill the "terrorists".
But this is kind of interesting. Why are we drawing parallels between 9/11 and bombs? 9/11 was perpetrated by Saudi's with box cutters. No bombs were used or required. With all of our bomb sniffing/detecting/fondling methods, 9/11 still would have happened. We are not safer.
So, your argument boils down to: if we drop the theater and go back to metal detectors only, then 9/11 style hijackings in the US would be "common" again (mind you they only ever happened once on US soil, hence the date describing them)? Also mind you, they had no explosives, etc. Just box cutters.
Sorry, but no. Case in point, even with "enhanced" security we still had shoe and underpants bomber "terrorists" get through. Security hasn't gained us anything. Awareness of the fact that not all hijackings end up in safe landings has forced the public's hand in dealing with the threat in the air. We all but kill them now.
The attitude shift _alone_ will stop hijackings. Now random bombs in bags, ok, screen bags with dogs and sending them through scanners. Problem pretty much solved, or at least reduced to near zero, just as it was before.
Seriously, since 9/11 we have gone from a "let the hijackers land where they want and don't fuss" mentality to a "kill the fucker" sport mentality. Hijackings, at least on US flights are a thing of the past. Sure, ok, finding an explosive is a good thing, but at what cost? The chances of being on a plane with a bomb are so tiny it isn't even worth worrying about.
Lets go back to metal detectors to get the obvious and maybe walk bomb sniffing dogs through often enough to deter would-be "terrorists". Oh, and scan checked luggage all you want, just stop stealing from it, ok?
Nude photos and fondling my (and everyone elses) man bits isn't making me feel safer, it's just making me want to fly less and make me loathe my government even more. I'm spending less and the government is spending more. What a great recipe.
The solution of this problem is trivial and is left as an exercise for the reader.