[myWindoonn]

Is a scarcity of top-level research doctors the reason why insulin is expensive in the USA but not other rich democracies? Similarly, is a scarcity of luxury mansions the reasons why the USA has hundreds of thousands of homeless but not other rich democracies?

[myWindoonn]

No. The reason why insulin is expensive is because the USA has a free market for pharmaceuticals and allows manufacturers to set high prices. The reason why there are hundreds of thousands of homeless is because the USA has a free market for housing and allows homeowners to set high prices.