[T-N-T]

>Just look at the USSR: they had tons of bombs, and their government was toppled, from within.

I wouldn't use the word "toppled" in the case of the fall of the USSR. Nobody actively contributed to its fall with the desire of making it fall. The factors that caused its fall aren't even comparable to anything that would affect dictatorships like NK.

In fact it is far more comparable to empires of old. Like Napoleon's empire, the roman empire and so on. The USSR held territories which hated the guts of the people and culture that governed them, Russia. When Gorbachev led reforms to give more freedoms to the people, that allowed the expression of nationalism throughout the occupied territories of the USSR "empire". Once all those territories started using their freedom of speech to rally around ideas like being different from Russians and needing to form their own nation, the USSR was bound to cease to exist. Russia, the main core of the USSR, is still more of a dictatorship than a democracy, by the way. It is arguable that the idea of a dictatorship was never really toppled in the mainland of the USSR. The fall of the USSR as a system of governance was merely the loss of colonized land.

North Korea doesn't have any factor of the kind. The government will only change if its rulers want it to change. It's doubtful a starving peasant revolt could do anything.