Simply put, they do not know things can be better, and they wouldn’t know how to make them better if they did.
This sounds like the White Man’s Burden. The people who live in DPRK are well-equipped to know what makes a happy and healthy life. They’re not any more brainwashed/blindly obedient to “the party” than people in the West are.
While were at it, let’s just remove school entirely. Children could compete in the free market of unpaid internships and develop skills that will be useful for their working life. I feel like government has had a monopoly on education for too long, let’s let the free market do it’s thing and save the day.