Public health isn't just a question of who pays everyone's medical bills. For instance, federal policies drive the overproduction of fats, sugars and other empty calories, which makes junk food abundant and cheap in comparison with healthy food and encourages bad diets. That has to change, especially when we factor in the environmental consequences. Diet is a big part of the reason for Americans' relatively poor health outcomes despite an unbelievably costly medical system. But there's more, such as development patterns, which have an impact on public health and are skewed in an unhealthy direction by government policies and/or funding.
Americans with good medical insurance have access to great medical care, but the number of them having it is in decline and change is inevitable. And, since so much is spent in hopeless and invasive procedures to prolong life, but not quality of life, it's also inevitable that people eventually won't be able to demand every procedure they or their relatives might want to try at the end of their life.