Retail prices in hospitals take into account a high-percentage of non-payment...which is why they are high to begin with! They have complete correlation with reality: an uninsured person is more likely not to pay, so prices are higher so that works out. Now, the higher prices lead to more non-payment, and a vicious cycle ensues.
This is why the mandate in Obama care is so important, to stop this cycle.
For those who want to know more about that master price list and how its prices have little to no correlation with reality: http://www.time.com/time/magazine/article/0,9171,2136864,00....