That's an overly simplistic analysis. Japanese game designs have led globally since the mid 80s and it is only recently the west has sort of caught up. An entire generation of gamers have grown up with those characters, content and sensibilities ingrained and it is why Japanese culture is popular in the West. Nintendo's R&D software teams are mostly in Japan so their software, as cultural products, reflect for the most part, Japanese sensibilities. But the reason they're successful, is their content is global is nature. The same applies to the other multi-national software developers in Japan,justchris said:Nintendo is a Japanese company. I think they were just more focused on the Japanese market and what was wrong with it, which is what led them in the direction they're going. And now they're trying to push the rest of the world in the same direction Japan is already going.
They are from Japan but not of Japan. When Nintendo was least successful was when they tried to cater exclusively to their perceived hardcore fanbase and when they thought their strength was to simply run every franchise they had to the ground, I'm glad that phase is over.