This paper is a good assessment of the situation and how it could unfold in different directions. It starts with an assumption I share:
A crash landing is probably not imminent but in the mid to long run, it may be virtually inevitable.When collapse occurs, it will almost certainly catch everyone, including Pyongyang elites, off guard. In theend, all trajectories may ultimately lead to a crash. Soft landings and suspended animation could turn out to be mere way stations on the road to final impact.
But when this happens is another thing. It may have to wait the death of Kim Jong-Il as other totalitarian states have demonstrated. And as the author notes, those who have predicted North Korea's imminent collapse the last fifteen years have a lot of crow to eat since the regime teeters on despite its weakness. The signs of collapse have been visible, as I've noted many times when wondering if that sign was the final straw; but the point when those signs add up to enough to collapse the regime is really unknowable. The paper outlines what signs to look for in various areas to judge whether the collapse is upon us.
The paper also distinguishes between the collapse of the regime and the collapse of the state. I confess, I've often assumed that a collapse of the regime means a collapse of the state. The paper notes that Poland and Romania saw the regimes collapse but the states continued. In East Germany and the Soviet Union, the regimes collapsed taking the states with them.
North Korea, it seems, would therefore be more likely to experience a regime collapse than a state collapse. East Germany had West Germany ready to absorb the failed state while the Soviet Union, being an empire, had component parts ready to strike out on their own. South Korea does not want to play the role of West Germany and unless North Korea's neighbors actively seek to partition the country after a collapse of the regime, I don't see fissures within the state that logically indicate that separate regions would want to go their own ways.
This should actually be reassuring to South Koreans who don't want responsibility for North Korea. If providing goodies to prop up a beastly Pyongyang regime was the price to pay for avoiding the responsibility for the north, that policy at least made some sort of sense even if you had to live with knowing you condemned northerners to a hell on earth. But if squeezing North Korea doesn't mean absorption after a collapse of the regime, then this policy is both morally more palatable and less likely to impose crushing costs on South Korea for the next generation or two.
Basically, the Pyongyang regime is doomed since it won't stop being the regime it is on its own. And that regime cannot cope. But the time frame is anybody's guess.