

On the other hand, popular Japanese idols have don't have high quality skills in singing. This is because Japanese people don't consider idols as artists/singers, they consider idols as entertainers. The main role of an idol in Japan is to make people happy and to be on television shows. This perspective is very different from that of Korea, where idols are also expected to perform at the level of an artist and also be a good entertainer.
Another possible reason of the K-Pop boom is the small Korean music market. Along with the fierce competition, Korean idols have to expand their market to Japan and other Asian countries. Although the Korean music industry is full of amazing artists, they all cannot profit from Korea's small music industry. Moreover, since illegal downloading is widely spread in Korea, Korean artists cannot earn much profit by selling albums just in Korea. Therefore, many artists aim for the Japanese music market or the Chinese/Taiwanese markets. In order to succeed in these foreign markets, K-Pop stars must produce high quality music and perform well on stage.
With these reasons being said, K-Pop stars having such a dominant role in the whole Asian music industry is not an unusual result.