Cannot speak for the cause, but the prices are distorted. I was taken to ER a couple of months ago and x-ray of chest cost $3500 and CT of chest $5500. The equivalent prices at the private sector of my home country would have been $70 and $120 and I could have gotten those done just as quickly as in ER in US.

In most places in the US, you can't even get list prices. Calling up providers for quotes gets you hung up on.

Singapore, which has a significant market portion to their health care industry, mandates posting of prices.

I've actually found that you can get list prices from hospitals. The problem is that they're distorted and sky-high and not necessarily very reflective of what you will have to pay if you have insurance, because the insurers have negotiated their own rates. Those rates are treated as top secret by everyone involved (that is, until you get a bill).