What is wrong with the caveman strategy? First, it slows everything down. The purpose of air-travel is to increase the speed of travel. Secondly, it makes air-travel more expensive and damages the economy. Third, benign private possessions are stolen (it only counts as seizure when it is reasonable). Fourth, it doesn't work.

In any security system, the security people are the vulnerable point. You can pay them to let you through, or you can kill them or incapacitate them. If any of those methods fail, you can become a member of the security team. This is why, above all else, the caveman security method is a failure. It worked in nature because animals are dumb. The only real method of stopping hijackers/whatever is to find them before they reach the airport.