I think your giving them too much credit. These religious wackaloons aren't motivated by money, there motivation is hatred of anyone who is not of their faith and beliefs and spreading those religious beliefs and killing those that won't buy into it. This is backed up by there forcing people to either convert to their form of islam or killing them by either shooting or beheading them. End of story!
The reason we can't "end them all" is that yes, we have a mega billion dollar defense budget, high tech weapons and highly trained special forces, but they have thousands of members and are spread out in several countries and without knowing exactly where each one of them are, it's difficult, next to impossible to take them all out, short of using nuclear weapons. Special forces are only good for taking out small groups and you have to know exactly where they are, if you think otherwise you are playing way to many video games.