Navy? 708 vessels vs. 160. Air Force? Over 1,500 vs. 500. Granted, it's in the Air that differences in quality will mean the most, but the Norks can use what are basically suicide planes to keep the South on defense in the air for crucial hours or days before the ROKAF could focus all their attention on ground attack. Those hours or days would be crucial, probably decisive.
And all of this comparison ignores the fact that the artillery barrage starting a Nork invasion would probably be the largest artillery barrage since the world wars, if not bigger.
Bottom line: The ROK is already doing what it needs to do in order to defend itself, and it will not be enough. Anyone who says this is none of our affair can say that. But if they say it, they must also say that they are comfortable ceding the Korean peninsula to the Juche Fruit family. To say otherwise is completely unrealistic.
China would hate this.. but first the Americans would have to completely GET OUT...