It's not at all clear that North Korea would be allowed to follow the same path that China did. However, the point is completely irrelevant to the discussion. Again, we are not evaluating the North Korean government or their domestic policy, we are evaluating whether they pose a credible military threat, both in terms of their aims and their capabilities, and the answer to that is a resounding "No," by your own admission.
In any case it's incredibly hypocritical to lecture another country about their military spending while the US is spending more than the next 9 countries combined. You can't pretend that you have some principled commitment towards deescalation if you're just focused on getting weaker countries to put down their arms so that powerful countries can dominate them. That is just imperialism, plain in simple. You might as well be a British colonizer calling for Zulus to not be so militaristic and to put down their bows and arrows, as they slaughtered them with machine guns.