You're making a hypothetical argument when you don't need to. Since we're specifically talking about insulin, and not placing an arbitrary cap on any drug, there's no need.

We know what it costs to manufacture insulin, and it's literally a few bucks per vial [1]. You're framing this as if it represents the larger debate between fixing medical costs and the free market, but it's not that at all, and no one is going to lose their insulin.

[1]: https://www.businessinsider.com/insulin-prices-could-be-much...