How can ISIS out do USA Russia Europe etc

It seems implausible that the amount of $$$$ and resources USA, Russia, Europe even Australia in our army's, airforce and navy's. Yet with the whole lot together we as a world group cant defeat ISIS...
In a simplistic way, the world could just put all war effort globally into destroying them, surely they wouldnt have a chance, in some ways its like they dont want them beaten, and its some kind of a game.

Maybe I seeing the situation wrong but , something doesnt seem right...