It’s just a plan dude. Plans can change and be foiled. God allows evil to triumph and be defeated according to His will. Korea is a small part of the puzzle/plan.
As an example, birth control is now used almost everywhere in the west. Yet it was invented in the 40s, almost 80 yrs ago. Took that long to condition the people and to erode morality so that the population in the West would decrease. But that part of plan has succeeded.
You can look at modern history in 2 ways - accidental or planned. Most major events were planned.