We can and should have lots more doctors (and other primary care providers), but we've long restricted that because people have wacky ideas about things like economics and intelligence.
Boy howdy.
There are three major parts of the economy which are extensively regulated to achieve political goals: health care and higher education (on the national level with some state involvement) and housing (city-level zoning, with occasional other mandates particularly in places like California).
Notice then the three areas where prices have become radically more expensive over the past several decades, fomenting a crisis that threatens our prosperity as a nation: housing prices, higher education prices, health care prices...
Canada has more regulated health care than the US, and yet the health care has better outcomes and is delivered at a lower price. It isn't perfect, but having seen both systems, the Canadian one is overall better.
One of the reasons, although not the only one, for higher education prices is less subsidies for education at the state level.
I agree that city zoning, and the lack of quick public transit, explains much of the increased price of housing. But some of this increase in cost is due to increased population, and the amount of land in and close to cities being fixed. Higher density would help, but higher density housing to also more expensive to create than lower density housing. A lack of regulation also leads to outcomes like houses in Houston being build on flood plains.
There is a role for government and regulation, and a role for free enterprise, but to understand the balance one need to look a other countries it see if they have a better balance and what works well.