This might be rigth but I don't get a lot of confidence from the start comparing Japan's lifespans to the USAs and implying it's because of health care

Japanese, as a whole, have a vastly different diet than the average USAian. As a whole, they are far less obese, eat far less diary products, over eat less, eat less meat, etc... Again, not saying that's the reason but it's a possibility. USA = 2500 calories a day. Japan = 2000 calories a day. Japan = 3% obese. USA = 33% obese.

Next up is exercise. Sure, lots of people in the country live in rural areas and drive a car. But some large portion of the population does the majority of their commuting and shopping by walk/bus/train/bicycle. That means that on average, Japanese get more far more exercise than the average USAian. Japan gets ~25% more exercise on average

I'd suspect these 2 (3)? are the major reason Japanes live longer. (1) they get more exercise (2a) they don't over eat (2b) they eat healther foods.

Anyway, the point is, the post should arguably not be putting such a specious statement at the top. It suggests the rest is probably just as specious