DPRK is not opening up like China any time soon. China had to open up because they had no alternatives. They had hundreds of millions of very poor people, no industry, no infrastructure, and a fallout with their biggest and most advanced ally.

DPRK is in a much better spot with functioning systems, infrastructure, and a working political system. Once the US collapses, they'll be able to trade more freely and SK will seem like the forgotten section of what used to be Korea.