It's true that the economy in North Korea has, to some extent, been stimulated by areas that are often on the border, especially the border with China, which allow joint projects. The Economist magazine last week reported that the economy of North Korea grew by 7% last year. Whether or not that's true, it certainly has improved. But whether that gets into the pockets of all the people of North Korea is the point of your question.
The North Korean regime has a so-called songbun system, which divides people up in a kind of caste system. Actually there are 55 subcategories, but essentially there are three categories. There is the core class, who are the friends of the regime. There is the wavering class. And there is the hostile class. These are old-fashioned communist-type words. Most people are not in the core class. Most of the core class live in Pyongyang.
It is in the interests of all people in North Korea for the economy to improve. With improvement of the economy there will be a trickle-down effect to all people.
One of the most interesting people I met last week in Seoul is a young man who, outside of North Korea and Korea, has established a business through which he is engaging with some of the escapees. The point he made was that when they get the smell of the capitalist system, they are full of energy, ambition, and a desire to do as well as their cousins do in the south.
South Korea is an extremely successful economy. If the North Koreans can get some of the same attitude and success, their economic position will improve. But sharing it around is going to be very difficult.