That is the problem with asymmetric warfare.
As the west puts together a very expensive, top heavy military threat to ISIS. All ISIS has to do is get a disillusioned guy to drive a truck into some non-military targets. All over the world are dissillusioned guys with access to trucks, various janitorial chemicals which can be combined in the wrong way, and in the United States, large capacity firearms.
The west is not willing to pointedly attack soft targets in the way that ISIS does. Not sure that ISIS even has such soft targets to be held dear honestly.
Even if NATO gets off it's collective ass and rolls down to Iraq/Syria with their full air power in effect, they will still have to mop up the remnants with boots on the ground. Exactly the type of conflict which there is not political will or economic backing for.
And if there were, that is exactly what ISIS wants. A big romantic east vs west conflict. In technicolor.
Honestly the Pentagon needs to go back to working on that gay-bomb idea they had back in the 60's.