They have chosen to run concentration camps and starve their own people for decades instead of becoming a rich country like South Korea. They can stop the sanctions whenever they want, by becoming a democracy.
Friendly reminder that this was never about democracy. The US imposed a military dictatorship on South Korea that was even more brutal than the North. The goal has always been promoting capitalism at all costs, and nothing else.
The people are starving because North Korea has been cut off from the global economy for its entire existence. In other words, the people sanctioning are responsible for the starvation. Sanctions obviously do nothing to hurt the ruling party or coerce them to change their views.
Educate yourself on history before lecturing us on democracy.