Communism is not political governance but a direction. There is no goal of Communism other than controlling a population. When everyone "owns" everything, nobody owns anything. Therefore it's really tyranny. Tyranny never ends and is fluid.

It'll never be real communism. Real communism became obsolete with the first trade between Ughga and Gruuu; while establishing a system of value to different items.

Communism only works when everyone has the same idea and that only happens in very small groups. A group of 20 living on a commune where they kick anyone out / or allow people to leave who does not believe in the ideals? It works.

Scaling that up and forcing people to be in the commune? Hell no. It's a tyranny.

Now do the fertility rate on each side.

While the comparison is true imho, there's much to learn about Korean history. Highly recommended watch