The situation is the same in all the nations in this world. There is a part of the population which lives in luxury, and there is another portion which lives in abject poverty. And the majority of the population always fall between these two categories, constituting the middle-class. However, in North Korea, the poor outnumber the middle class by a wide margin.
Yes. It has always been so, there must be a balance between the poor and the rich. But in this country they do not worry at all about the economic situation of the population.
Even Kim Jong Un needs to worry about the economic situation in his country. Else, the people will rise up in revolt and topple him. That is the only reason he has granted some freedom for the general population recently as far as small time trade and privately owned business is concerned.