The various medical cartels have lobbied to artificially decrease the supply of competitors, workers, and companies in the healthcare industry.
Single payer healthcare doesn't magically create more physicians, hospitals, or drug companies.
If republican voters aren't willing to replace their politicians with ones that are willing to vote and make a single payer solution, then they don't care about single payer healthcare that much. It has nothing to do with any specific implementation. Republican politicians have never put forward any sort of single payer healthcare implementation
Patents are the same. Residencies are the same. Hospitals are the same.
Do you think the physician cartel is going to stop living in Mansions?