You could fix every problem with healthcare and Americans would still die early. Eat crap from childhood and there’s nothing doctors can do. Preventative care starts in the cafeteria.
There is a culture of crisis management in the US when it comes to all health issues. This is the direct result, along with all the inefficiency you mention, of private for-profit health insurance.
Have you seen what grocery store are stocked with? There’s not even enough food for everybody to eat healthy at once if everybody simultaneously saw the light.
If we really wanted to solve the problem in a major way, we would literally do things like cap the amount of sugar and HFCS producers had to work with, to pre-empt this educational revolution surely causing people to throw out their fruit loops and simultaneously adopt healthy eating. Most of the food industry is controlled by a small number of conglomerates, it would be easy, but we won’t instead we let PepsiCo kill by the millions.