In the initial era of the split between North and South Korea, South Korea both was run by a bunch of people who had a history of outright killing leftists, and the United States was involved in similar actions.

The lack of serious offramps to reunification, along with not as huge a delta in quality of life between north and south for a long time (aid from other countries sure helps!), allowed the DPRK to establish itself as its own nation.

Now there is the surveillance state apparatus allowing the DPRK to exist in its current form in perpetuity. And even if tomorrow they showed up and said "let's unify Korea", South Korea (even ignoring all the ideological reasons it might not want to) would likely be unwilling to absorb an extremely poor country and pay for it (see the painful experience of Germany's unification).

There is probably no off ramp that exists unless people are willing to let the elite walk away clean from the situation in one way or another, and it seems hard to imagine such a future.

And if you are a north korean elite and you are allowed to travel to northern china, you will see a place where things are running more smoothly, but you're still going to see places with massive amounts of internal controls and restrictions. So who's offering the upside to some regime change here?

> see the painful experience of Germany's unification

I had thought that Germans from both sides were overwhelmingly supportive of re-unification, even if it would cause short-term pain??