> Demand for treatment of a life-threatening, painful, or debilitating disease does not depend on the price or the quality. It's not a free market at all because consumers have no choice but to buy at any price.

If this were true, wouldn't this be true: Demand for [food, shelter,..other necessity..,] does not depend on the price or the quality. Markets for this good can never be free because consumers have no choice but to buy [food, shelter, etc.] at any price.

Don't consumers always have a choice at least to the degree with which they have choices of whom to by from?

Food and shelter are classic examples of necessary goods which the government provides through taxation to those who can't afford them.

Government subsidization would only put more upward pressure on prices though. And yet, food does not cost infinity dollars. I wonder why?

Inelastic demand doesn't imply infinite price as long as there's competition among suppliers.

Government subsidies on the demand side would put upward pressure on prices, but government subsidies on the supply side put downward pressure on prices, and there's a lot of supply-side subsidies.

I tend to agree, but to be fair, some of this would be mitigated if the market were truly free. For example, the lack of competition issue would be largely resolved in the absence of patents that grant long monopolies to single companies.

The government doesn't produce them or set the price, they merely buy them. It's still a free market.

You're talking about demand, which is orthogonal to competition. There are plenty of inelastic demand industries which are still quite beneficially served by competitive markets. And that includes things in the realm of goods and services that are quite literally life saving.

≥ If vision correction surgery is too expensive for you, you can wear glasses or contacts instead and be totally fine.

As someone who had lasik to correct a 9 dioptre astigmatism/myopia, I can tell you there is a world of difference between prosthetic correction and native correction. It's not just in terms of comfort. I can see better than I did with the perfect prescription glasses. I have a much wider viewing angle. I don't have to worry ever again with lens angle rotation.

For high corrections, glasses are anachronic, and should be considered the wrong treatment.