I feel that there are a load of things that the characters could have but are not shown, and I also have some theories behind them. Take for example Japan. I feel this is the explanation to why Japan acts old, it's a reference to Japan's population. In Japan the population is decreasing,aging and close to a quarter of the population is over the age of 65, not to mention that the median age is 45. In fact the government is giving more financial benefits to people who have children, and are actually paying people to have more kids, because they say if things don't pick up soon 40% of Japan's population could be over the age of 65 in 50 years.