Why Are Japanese-Developed Games Less Popular?

Thanks to GameSpy for their 'Sole Food' editorial discussing the decline of the Japanese-developed videogame in the U.S. console charts. The article doesn't deny there are still big Japanese-developed hits in the West, but suggests: "It's not uncommon for there to be only two or three Japanese games among the top 20 sellers each month; this would have been unheard of less than ten years ago." As for explanations, it's argued that "Western developers are doing a better job of servicing core genres that are popular in the U.S.", but a "financial and creative slump" in the Japanese games industry is also blamed - "A quick glance through the games shown at last weekend's Tokyo Game Show reveals little that is truly new."