They date. They have sex. They marry and have children to replace them when they're too old. Problem solved for you?

This question and every answer to it here will be oversimplified. Think about it like this: "America. You voted for Trump. Is it true your whole country is racist?"

Everything else you can see from numbers alone. Birthrates are falling. Yes. But that is not really unusual for a modern society.

Do they have prostitution? Sure. Western countries do too. Does that mean everybody uses their services? Nope.

And yes. Working long hours is part of the problem, but the younger generation seems to be somewhat discontent with working so long. Same how in the west people complain about the baby-boomer generation. Also there have been incentives from the government changing that ridiculously work focused opinion for a long time. Stopping all trains after 11 was one step. Didn't work out. Currently they are promoting employees going home earlier the last friday each month.

It always feels weird reading about this stuff. Hexk. When I was in Japan I read about the refugee crisis in Germany and media made it look like everything goes to shit. Came back. Not much changed actually.

And no: They are not actively looking for westerners helping them out. Actually you will have a pretty hard time becoming anywhere close to being accepted in the society to begin with and when you work there you will also be a subject to their work culture.