I've been thinking about this kind of cost thing all along. Defense costs a lot, accurate offensive weapons are very expensive, but thug states like Russia and Iran can and do build cheap terrorist weapons to kill, maim, and destroy. The only trade off I can find is in what might be saved by a high priced defensive weapon instead of looking at it as simply the means to destroy a cheap terror threat. The real cost differential is in dealing with drones. I'm still thinking something far cheaper like super shotgun rather than expensive guided munitions until sophisticated and higher flying drones become the norm. We don't go bird hunting with rifles, and shooting down some current drones should be considered much the same.