I would not see the decline in the success and prestige of Japanese consumer electronics only as a story about being undercut by increasingly competitive South Korean and now Chinese products. Sony and other Japanese manufacturers missed the boat regarding the PC and software-driven development in the 1990s and never seemed to recover, thereafter they have always been on the defensive.
Note that Japan did not lose its dominance in music (Walkman, CD) to SK or China, but to USA with the iPod -- which in turn laid the foundation for the success of the iPhone, another development that Sony was not ready for, leading it to fall in with Google's Android (like everyone else) and in turn opening the door to commoditisation. There was a cultural blindness here, or inability or unwillingness to adapt fast enough, to get ahead of the curve and dictate the path that others would follow. There are lessons here for China.