Collect premiums via payroll taxes->fund healthcare providers. That greatly simplifies it, but there are many other first world models we can pick from. This is not hard.

I entirely agree with you on that and your assessment on how the finance/tax part of it is not as scary as some would think, it might even perhaps not be the hardest part of the problem.

My personal belief in single-payer is that it is the only way to create a leverage to either create a public offer of healthcare goods and service, or radically modify the power imbalance and drive the prices of goods and services way down. The thing that worries me is that in both cases, what I understand as being a total healthcare bubble, which I am sure is a well organized lobby, won't exactly be thrilled at letting things happen without a fight :)