Software is as much a cultural product (like books, movies and pop music) as it is a technological product. All human interfaces exist in reference to expectations and assumptions based in culture and language.

Japanese culture isn't compatible enough with "the west" for their cultural products to have a world wide market, aside from niche things like anime. This combined with "winner takes all" markets makes it difficult. Basically, they can't expand services internationally that work domestically.

Individual Japanese developers are brilliant.