My comment should have said that absent insurers over that time period, prices would be higher than they are currently. The effect they have is on controlling the level of price increases, not on lowering price absolutely (which I doubt is possible if people wish to keep extending their lives).

I am not saying that insurers are the most effective option or advocating for them; I am only saying that without them, prices would be significantly higher.

If you need evidence, simply compare the total price of any health care service (i.e. total cash outlay by all parties) between a person who carries health insurance and a person who does not. Universally, the price of the service is higher for the uninsured as they lack negotiating power.