It seems our technological capabilities are highly exaggerated.
Personally, I don't think it's too difficult to believe that the Taepodong-2 failed (wasn't destroyed by our anti-missile defenses). As opposed to the Scuds which were provided by people who more or less knew what they were doing, the Taepodong-2 is something of an indigenous design. I have no doubt that North Korean quality control stinks, and even with technically proficient countries, things happen, particularly when testing new technology (Project Vanguard ring a bell?).
Also, how exactly do we know what type of range the Taepodong-2 has? I've reports that say it can reach Alaska and a few that say it can reach much of the west. However, we haven't exactly been able to see a test of its capabilities (at least until now at least). Are these numbers pulled out of someone's rear?
OTOH I also agree with you that our surveillance tech capabilities are exaggerated. Something as simple as a cloud can negate any optical surveillance from space. Some people think that it's impossible to evade infra-red from lower flying vehicles too. But every animal over forty pounds is another red blob on the ground.
The stuff works pretty good in Afghanistan and Iraq though where there aren't any trees or many animals. Have you seen any of the videos of C-130s taking out terrorists at night in Afghanistan?
It all depends upon a lot of variables. It's comforting to know that we have far better tech than anyone else in the world. As long as our gooberment keeps it aimed at enemies.