Does anybody have any idea why is it that way? Considering the obvious threat, why haven't they tried shifting away from there? I agree an entire city can't be moved, bu the "Capital" nature of it can be.
You could move the government, but it wouldn't matter. Seoul would still completely dominate South Korea. Their entire economy and around half their population is based in the Seoul metro area. It's only a mild exaggeration to say that Seoul is South Korea.