see also: the USSR, plus Japanese ultra-nationalism (banzai!!) during WWII
my point, anyway, was that it'd obviously end in North Korea's demise, but it's going to take lots of lives with it. It's not as easy as "well, let's go take em over!"
the USSR and the Japanese were fighting during a time where weapons and technology are nowhere near what they are today
armor, firepower and pretty much everything else has exponentially improved, meanwhile their technology has flatlined around 50s-60s era stuff
you're giving them too much credit, which is a good practice in wartime but still