......only a matter of time before the guns are turned on the government..... and this becomes the next american military sinkhole.

I don't think so. There has to be some advantage (perceived or otherwise) and in this case there's none. Better to let China take on the burden of reforming NK. They have more experience at demolishing personality cults (Mao) and can more easily move NK towards economic stability based on their own current model. Even if the USA were to step up, I doubt the South would support them. SK's economy is too small to absorb the North without major difficulty. Their tycoons and bankers won't allow it, and they, not the SK people, run the govt.

I'm just guessing of course, but it seems the more likely outcome.