In WWII we went on bombing raids and then tried to figure out if we hit the right city. With modern GPS & video - a healthy majority of smart bombs find their way to the right spot. We do have a lot of retrofitted "old bombs", however.
The cost of a miss is too high (doggone daisy bombs cost $18 million a pop). I suppose you could say the cost of the bomb is more that what it's destroying on the ground.