Remember, the ground people are wackos, waiting to die for their cause, so they can hit on the grape wielding virgins. These are STUPID people. They make a decent tools for the smart guys, in certain circumstances, but are not to be trusted in anything too complex.
I agree that stupid people (shoe-bomber) are easy to get and can't be trusted with anything too complex.
However, 9/11 showed that there are very smart, dedicated people out there with a definite agenda...and that they are willing to sacrifice themselves to meet their objective.
The good news is that, the supply of such people is pretty limited and sucicide attacks tend to use up their own numbers. :-)