Is there a legitimately good reason for all those treatments to be so expensive, or is that, to a large degree, capitalism extracting capital from the market? Why is American insulin so expensive when compared to that from other countries?

> Is there a legitimately good reason for all those treatments to be so expensive

We can't really know, since only free markets can determine the price of a good or service (it's driven by supply and demand) and health care market is tightly regulated.

> Why is American insulin

Because of the regulatory barriers not allowing other providers to enter and sell insulin on the US market.