>Not everyone is rich enough to have the time to exercise

For full-time wage earners, there's actually a slightly negative correlation between wages and leisure time - people who earn more money have less free time. There has been a major long-term trend towards greater leisure time across all socioeconomic groups. Unemployed and retired people are not significantly more likely to exercise than working people, despite their obviously greater amount of leisure time.

https://www.bls.gov/news.release/atus.nr0.htm

>can't even afford healthy food

The richest American households only eat 0.6 more servings of fruit and vegetables per day than the poorest. The overall average intake was 4.76 servings, so this difference in intake is clinically insignificant. Education level was more strongly correlated with fruit and vegetable intake than income, but differences within socioeconomic groups are far more significant than differences between them.

https://academic.oup.com/ajcn/article/87/6/1883/4754427

https://www.sciencedirect.com/science/article/pii/S014067361...

The shortcomings of American diets and lifestyles are a hell of a lot more complex than just a lack of time and money.