(emphasis mine)
Strongly disagree. What you refer to is a health benefits plan. Insurance should cover only unlikely events, not routine events. Just like your car insurance doesn't pay for new tyres or burnt bulbs.
As someone who does my best to stay healthy, I don't think my lifetime health bill will come to anything close to what I pay for insurance. But I want the insurance for the random stuff I can't control.
Especially when it comes to preventable diseases, good health insurance companies are doing some really interesting work on effective behavioral change and early intervention. My insurance for instance pays me to walk every day.
The ACA requires insurers to spend at least 80% of premiums on direct patient care. To grow profits, they must grow premiums.
But then the population doesn't have an incentive to follow that education and encouragement—at least not a monetary one. As a comedian said, "You see, I don't have to exercise, because I have health insurance."
Currently the largest medical payer in the US is medicare, a government program. It is also one of the most expensive programs the government runs. The government already has this "incentive" and yet we don't seem to be getting healthier nor do people seem to eat better and exercise more. People seem to be getting more obese, not less [1].
I don't know of a single organization or program that has managed to have long-lasting reductions in obesity. Diets routinely fail because people can't maintain them, and exercise by definition is hard so again it's hard to stick to. One fundamental issue is we don't quite understand why people get fat. It's not clear how the basal "fat" set point that everyone has gets set, but it is clear that deviating substantially from that set point is very difficult and that it might shift over time.
[1] https://www.stateofobesity.org/obesity-rates-trends-overview...
Single-payer tax-funded health insurance means that each person contributes based on their capacity, and nobody has to pay when they receive services. Then the tax collector has an incentive to increase effectiveness of health services by educating and encouraging the population to eat well and exercise daily.