Third parties payers is the reason. As a general matter if you have insurance - private, medicare, medicaid - and the reason isn't anything crazy / chronic then the price is never out of the world. Chronic conditions add up but the people in those cases generally know what the cost is ahead of time. And if you don't have insurance either you're able to pay out of pocket or you just don't pay and then get care anyway.

Which is to say it's all madness.

For a script you fill at a pharmacy? Sure, you can find out exactly what it will cost before buying.

Medical treatment by a physician or hospital? No, you can't really find out.