My favorite thing about single payer is when people spout off that it's free. No, you fool, it's not free. You pay for it with taxes.
I don't believe there is a single person in the UK who would say its free.
It's free at the point of delivery. Which is actually the point.
How much we pay in tax for the NHS is discussed constantly in the UK.
Even its harshest critics, wouldn't adopt the American model. It's far, far, too expensive, and wouldn't match what we have at the moment.
Preventative care is a primary factor, something we could do better at.
The positives is that it reduces infant mortality, reduces serious medical issues in later life, and has improved life expectancy.
The improved life expectancy is a double edged sword. As people get older, the likelihood of requiring medical care increases. So potential costs increase. This is the area that causes constant debate and discussion.
The area we need to improve is the care in the community for the older member of society. Medical intervention is excellent. If we could improve the community care, it would reduce the need for medical care and reduce costs. But it is easier said than done.