If pure cold economic calculation would be applied to public policy, it would become clear that healthcare is not just personal issue, good healthcare provides positive externalizes for all. Your neighbors good teeth are not completely unlike investing in a bridge or other public infrastructure.
If someone stays healthy and can work full time 5 years more because he had free healthcare, he pays 5 years more taxes, generates more profits fro employer, and consumes less medical services during his lifetime.
Those studies are hard to make because it's hard to measure medical outcomes. For example, for the Oregon experiment they couldn't look into differences in death rates because death rates were too low even among uninsured people. They had to look at cholesterol, blood sugar and other proxies for health outcomes, instead of the outcomes themselves.
This suggests that at some point further spending in health has diminishing returns and we don't actually know if we reached that point yet.
https://en.wikipedia.org/wiki/Oregon_Medicaid_health_experim...
https://en.wikipedia.org/wiki/RAND_Health_Insurance_Experime...