In USA Today says that Japan has welfare problems similar to France: "Japan now has about four working-age people to contribute to pension plans to support one of today's retirees. By the middle of the century, there will be just two workers for each retiree." The problem isn't the birthrate so much as the Ponzi scheme which was built off of one curve of that birthrate. France has used a high immigration rate (which introduces its own problems) and attempted EU overlordship to compensate, but still has to face options such as freeing the workweek to find its own level. Japan can't exploit neighbors or take in low-price labor the way France can... I'm not sure how that dynamic will play out over the next twenty years.