It appears to be a standard ritual to cite Japan's declining population as an evil in all discussions of things Japanese. Today the NYT refers to the declining population as one of the factors making life bad for young workers.
Actually, a declining population is likely a plus for young workers. It means less competition for employment than would otherwise be the case. Falling population should also lead to improvements in the quality of life that will not be picked up in conventional economic measures. For example, its transportation system will be less heavily utilized, allowing people to reduce the time spent traveling to work and for other purposes.