This fact doesn’t change the price of what he has been proposing. Also, I wasn’t only referring to health care. He has a lot of ideas. Free college, guaranteed free housing for all, medical debt and student debt forgiveness for all, free child care for all, increased social security, etc.
Nordic countries say hi! Those are all standard over here. We pay more taxes yes but we don't have to worry about the extra costs of the above, so it's a clear (to me) net win.
The US government spends more on healthcare than many single payer systems, and has worse outcomes.