I would guess that there's a much greater difference between the military and civilian cultures for the US than for South Korea, simply because the SK military conscripts all able-bodied males.
An interesting lack of selection bias which I had never considered. I presume that those choosing to be career officers opt-in or at least are chosen based on desire/talent/etc.?
The vast majority of conscripts obviously have no interest in continuing after their mandatory period is up, so yes, the ones who want to be career officers probably go in with that intention. There are probably some who develop an interest after joining, though.
