As an American, I'd like to bring our people home and leave Korea to the Koreans. Conversely, I also like having the bases and hardware near China.
North Korea is, and has been, in a downward spiral for a long time. The only real questions left are how far it will go before something breaks, and when (not if) it breaks up, will it go peacefully or not. Personally, my opinion is it will continue downward for another 3 to 5 years, and when it goes, it will not be peaceful.
SK may not be able to absorb NK but they could keep it as a “puppet state” as Tigerlikesrooster says, and raise the standard of living enough for them to be able to merge. It could take a decade, but at least North Koreans wouldn’t be STARVING in the meantime.
Remember the last press conference of the Politburo during the self-coup attempt? They were literally shaking with fear up there. The Soviet Union collapsed within days.
The NorK's could collapse faster than anyone thinks. All that needs to happen is for people in the Army to decide not to follow orders. Lose the fear, bring down the regime.