They figure to go back to "one" Korea one day.
That is indeed the bottom line. The SGooks are doing a large amount of work to prepare for the situation ala east/west Germany when they reunite. The Chicoms and the SGooks just recently agreed to build a new span alongside Freedom Bridge between China and NKorea to help handle growing business between the two. NKorea doesn't do much business, and doesn't have any money, but agrees to the bridge as long as the other two pay for it. On the NKorea side the road goes straight to SKorea. Kimmie gets to sit on the curb and watch the world drive THRU his digs.
Should GW decide to settle the NUKE question the plan won't involve SKorea except they might hear the F-117's take off.
As long as no NKoreans move south and "ick" up the place. You wouldn't not *believe* the xenophobia of Koreans. I'm looking forward to all the squealing and whining when the refugees multiply...