They do. But what would they do with that information? People in the late USSR were in a similar situation. Even without necessarily knowing all the details,

They do. But what would they do with that information? People in the late USSR were in a similar situation. Even without necessarily knowing all the details, the average person, and certainly the intelligentsia and people working in the intelligence services, had a growing awareness of the absurdity of it all, how different the rest of the non-Communist world was, and so on. Something similar is true in China, today. A person in China who wishes to inform themselves about China's history or recent offences against human rights, can at this point, do so, and fairly easily. But... then what? Can't talk about it. With whom would it be safe? Can't tell others what you've learned. Can't discuss your perspective. In my view it was not the truth that destroyed e.g. the USSR. It was allowing people to organize independently of state control. That, plus truth, was fatal. Both the Chinese and North Korean ruling parties have learned that lesson. It doesn't actually matter if a significant proportion of the public knows the truth. They can know the truth, alone, in isolation, unable to act on it.