2 reasons why the USA won't bother too much over the DPRK short term. 1) They aren't a manufacturing and distribution center of terrorism to the rest the world. 2) They are located in a relatively benign geo-political location. I don't believe the spread of communism is much of a concern anymore.
What irritates about DPRK is how they do all their ranting at the United States instead of China. They won't talk to China...they always want to talk to the US and only the US. They're like China's mutated, inbred, criminally insane half-cousin who lives in the basement.
Coincidence you should mention the DPRK. Last night I was looking through some fairly recent pictures of Pyongyang and environs. Peculiar place.
Photos of DPRK 1
Photos of DPRK 2