If there is something Korea doesn’t lack, it’s manpower.

The US troops are more likely there as a political shield. Indiscriminate bombing would kill them too, hence drag the US into war so any enemies of S Korea have to act judiciously.

> No hosting nation of imperialism has ever benefited

That's why Japan and Germany are some of the worst places to live in the world. Oh wait, I had that quality of life chart upside down.