Outside hot-war which would result in massive casualties in SK, there is very little more that can be done to NK...
So there being no choice is probably correct in this case. At least with other countries there is some ways pressure them, with NK not too much, and not for measly sums of money involved.
It's also ridiculously hard to get spies inside of North Korea. Covert action is incredibly difficult. Imagine trying to train a South Korean to blend in when they are a foot taller due to sufficient nutrition.
So there being no choice is probably correct in this case. At least with other countries there is some ways pressure them, with NK not too much, and not for measly sums of money involved.