The US and everyone else have everything to lose while NK doesn't.

BUT the last thing a regime like NK would do, with its elite living like kings (or like gods while their people are gaunt and low average IQ), would be to start getting serious with nukes. Because that's when all those fancy countries —with their comfortable stabilities— would have absolutely nothing to lose. Not a good move by North Korea.

The best option would be to just let it die a natural death (like Franco in spain). Because imagine if we did take out this Kim Jong Un (sniper on a roof? Poison? A "small" nuke?); who'se going to deal with a massive flood of hungry unskilled North Koreans the next day?

It's basically a regime holding several million people hostage and I don't think it really is a danger to anyone (not to downplay how horrible it is for their people). Swat teams can handle hostage situations easily, but nobody is interested in a shootout.