Food is more important to your health than anything a doctor can do for you. Why don't we have a food insurance program?
Answer: because it would obviously be stupid. Now ... defend the health insurance system.
I didn't think you could. The reason we have employer-paid health insurance can be traced back to WWII wage and price controls. Desirable workers could not be paid more, but you could give them free health care. Employers did, and didn't stop when the wage controls went away.
Now we're stuck in the ridiculous situation of treating people like cars, doctors like car mechanics, and insurance companies like car owners. The car has no say in how much maintenance it gets, nor how much that maintenance costs. Consequently, it demands the best maintenance, price be damned. Any wonder that lots of people can't afford health care unless it's paid for by someone else?
Health care should be cheap and readily available, like food.