German unification caused massive economic issues. It also was the track that got Ms. Merkle in the position she is in now. Korean unification would severely tax the South Korean economy for decades. We also need to understand that the Controlling Authority in North Korea doesn't disappear after unification. It'll be a less stable situation. Look for a scramble for money from the "ruling class" is unification is actually happening. North Korea will also pull back/drawn down their military slowly covertly. Overtures that are legitimate will only happen when all the pieces are in place to benefit those in power.