I have a buddy who is skeptical of single payer. His main question is:
"Under single payer, how would my fathers private practice work? Would they be government owned? How would they make money?"
It's a fair question I don't have a great answer to off the top of my head. How would I answer that? Is it as simple as government subsidies would cover it?
To reiterate what other people have said and highlight a key point of the power of single payer, the private practice would work the same as it does now, but the government pays the practice for procedures performed. At least this is how it works in Canada.
So, the doctor can bill the government for every patient seen, every prescription, every referral, every procedure - at the rate agreed upon in the government billing rate schedule
This is where the power of comes into play. The government works with doctors to set reasonable costs associated with procedures etc., and then every practice, hospital, etc. gets to bill the government the same amount. And these prices are not set based on market rates but on real costs and take into account materials and salary and overhead.
This means that prices are standardized across all practices, and that billing is made simpler for practices and hospitals.