You: 1) overestimate the number of such planes the US has at it's immediate disposal 2) overestimate the effectiveness of artillery triangulating systems 3)

You: 1) overestimate the number of such planes the US has at it's immediate disposal 2) overestimate the effectiveness of artillery triangulating systems 3) underestimate the shear size of the DPRK forces 4) overestimate the amount of time each artillery position would have to be active to kill thousands of civilians in a densely populated metropolis. And finally: fail to take into account that if you've had this idea, chances are people who do military planning for a living have probably thought long and hard about it as well.