Paul, in the abstract i quite agree with you. The situation that you are speaking of is quite a difference in degree from such units as an Abrams, Bradley or any Fighter Jet.
If an Abrams gets "killed", at the most one tank crew dies. (btw, we lost three Abrams tanks in Iraq this time, no deaths thank God!), if an F-16C goes down, one man is lost. We will make modification as needed, and the discovered problems will be eliminated.
The Theatre Missle Defense system is currently undergoing testing, as your graphic stated. If that system fails to intercept one time an entire city is incinerated, or a large portion therof, not to mention colateral deaths due to shock wave and fallout.
Due to the nature of an ICBM, you only get one shot at it. They travel at Mach 13, faster than any SAM can move. In point of fact, the SAM can explode right beside the ICBM, and the fragments of the blast cannot catch up with the missle. The only viable options are to place the debris "cone" of the exploded SAM in the path of the ICBM at a certain time, or achieve a "skin-to-skin" kill. There are a great many variables involved under ideal conditions. i think that we both know that in those circumstances, conditions will be a great deal less than ideal.
Do not think that i am going "gloom and doom" on you. There is always an alternative. The nice thing about ICBM's is that the people who develop them are not stupid! The warheads do not arm until they are over target. The reason for this is simple, no one wants to incinerate their own country, and if the missle goes bad that would be the result. The DPRK has done enough testing that we can locate the missles and destroy them before they ever launch.
A better solution would be to take out the command and control ability. The DPRK communications systems are primitive. A high altitude nuclear blast kills it with EMP, and doesn't destroy anything else. Cruise missle strikes on key facilities disrupts them sufficiently that they cannot control their military. The order of battle for the DPRK allows for no initative in subordinate commanders, their military is impotent at that point.