South Korea is in a birthing crisis right now, so it won't much longer, and the photo does not show enough of China to show you that China does shine brighter. There are none of the major cities in that photo. The largest in the photo is Shenyang, which, of course nobody's heard of.
If the Picture shifted just a tad to the left, then you would see Tianjin and the capital, Beijing, both of which massive cities, right next to each other shining.
North Korea is a failed socialist state. China and Vietnam are both successful socialist states.