[lend000]

Keep in mind Australia has ~40% more doctors per capita than the US [0]. And the supply/demand curve is not linear, so physician shortage alone can account for a significant part of the price difference (note that Singapore and Japan are noteworthy exceptions to the doctor/quality ratio). As for why there are fewer doctors in the US than most developed countries, there are a number of potential reasons, and there is no reason to believe that any of them would be solved by the government subsidizing healthcare. You might just get long wait times like Canada and the UK (with comparable, but still higher physician counts than the US), which are sort of the jokes of socialized medicine countries.

[0] https://data.worldbank.org/indicator/SH.MED.PHYS.ZS