[solidsnack9000]

Japan's policy problems seem to be (a) underinvestment in people, (b) poor labor policy leading to over work and (c) population decline due to people's difficulties facing such an environment.

How does immigration help? Say some people immigrate next year. They stick around. They become Japanese. Their children are (a) trained in the Japanese way and (b) find themselves subject to the same labor policy as other Japanese. What has changed?