I think single payer is the way to go, but it, just like ObamaCare or the Trump plan, depends on healthy people paying more than they (think they) need. With the Obama/Trump plans, it comes from people being pushed to buy insurance. With single-payer, it comes from being taxed regardless of your health. I'm not sure Americans are ready to do that. 

On the other hand, a tax based on income would follow the health of the payer on average... don't pay much when you are young, pay into the system as you earn more, then get more medical care after retirement.