It's a consequence of the political system in North Korea and Chinese support. The industry of the north grew faster and was larger than the south after the war. Eventually the economy of South Korea overtook and then greatly surpassed the north. China support = not wanting the Americans to win but wanting to keep North Korea a poor subservient state. Is America as bad? Sometimes, but I think plurality of leadership thought in the West always tempers the worst instincts of their nation states.