I think there's a difference in timescales to what we're talking about, which I was trying to get at by saying "broadly correct, but acutely inaccurate". Over the past generation or so, the things I brought up are getting worse and I don't see anything that makes up for them. If you look substantially further back, then I agree with what you're saying.

We're talking about society, here, so it's not directly relevant that an individual is capable of being healthier today, because most are not taking that opportunity. That's the nature of societal decay: taken in aggregate, important things are trending down.