I admit an invasion is unlikely, but when NK loses the backing of east Asia then knocking out Kim, by some means or another, becomes an option.
Again, "drying up NK" to the point of collapse isn't an option for the west. North Korea's main import/export partners are Russia and China, with the latter being a powerhouse of export. In addition, NK produces what little food and trade goods it has on its own, with no aid from the west. There's nothing the west can do that doesn't involve the military.