It wasn't enabled by Japan's demographics, it was enabled by the world's demographics relative to Japan. Japan has had to deal with a mass-aging demography in a relatively friendly global environment. They've had the latitude to experiment and develop various approaches.

Germany, South Korea, and others are going to hit the same problem in a much more hostile global economic environment, as most of the wealthy global consumers are going to simply disappear. At present they're woefully unprepared to deal with any of it.

I don't think so. As I said, those other countries didn't have the same relative demographics as Japan. This just sounds like a fringe theory that isn't really borne out by evidence.