The NK regime has survived, to date: two major power transitions, the financial collapse of its protecting superpower state, the worst famine in modern history, a full-scale ground and air invasion by a world superpower, a widely-known and well-documented human rights record that would shame Nazi Germany, openly kidnapping foreign citizens to be trained as spies and other major diplomatic kerfuffles in the same league that have previously started wars, and I think the longest and most severe economic isolation in the history of the United Nations.
We're told breathlessly with each new development for the past 50 years that collapse is surely just around the corner. But I can think of very little that would seriously test the regime beyond what they have faced so far.