[PilotMan]

panerd your solution is akin to ignoring a difficult situation because it's too inconvenient to keep a handle on. Whether it's important or not is irrelevant because it's too much trouble to be effective. Parenting is a lot like that too. Sometimes you spend hours on the little stuff and it doesn't seem worth it at all. But if you don't do it, or give up, the magnitude of your failure, by quitting, becomes even more apparent.

IMO, jets are scrambled to provide first hand information to the people who make the hard decisions. The can see what's happening. Pilots inside the jet can also communicate with fighters to see the condition of the airliner if something has happened. An extra set of eyes outside can really give you a better feel when you can't see it all from up front. Fighters scrambled on 9/11 could have made a significant impact. The shoot-down option is always there, but hard to get to.

The cost of scrambling 2 fighters jets to intercept a jet is pretty small as a function of the amount of money that the military spends on aviation fuel and airplane maintenance. The idea that "we keep a police force that patrols, but if something actually happens it's not worth it to send them out" doesn't really make any sense.