Yes but it is also because those specific types of treatments respond well to market forces: they are common enough for there to be a lot of competing providers, and if the price is too high, people can elect not to receive those services.

For a counterexample, look at dental surgery. This is also often not covered by insurance, but it's much more expensive, and low-income individuals often take on debt and risk their financial security to undergo these procedures because the alternative is often a severely degraded quality of life. The difference is that the demand is much less flexible, so providers can get away with higher prices. Many healthcare procedures fall into this category.