You don’t defeat something like ISIS by killing off its soldiers. They have an enormous pool from which to recruit and we can’t kill them all. And, if we keep using expensive missiles and guided bombs to kill them one or two at a time, trying to do so will bankrupt us.
ISIS doesn’t produce anything - no weapons, ammo, food, refined petroleum products, medical supplies, etc. They are are able to loot some, and sell some oil, but not enough to keep them going. So, somewhere, they are buying these things, and somewhere they have sponsors giving them large quantities of money.
We need to interdict these supplies. Convoys should be destroyed, and ships should be sunk. We should cut them off from everything they need to keep going, until all they have left are rocks and sharp sticks.
We also need to find those sponsors, kill them and steal or destroy their resources. Likewise, anyone doing business with them, also needs to die and have their resources stolen or destroyed.
State sponsors need to see the folks responsible die in horrible and painful accidents and, likewise, they need to start having major issues with their most important infrastructure.
News flash. WE have been the source of their equipment.