A large part of it is that hospitals bill the maximum the insurance will pay, there are no cost controls of any kind so they submit a high bill and then it gets reduced to the max that can be paid. Another part of it is that the hospitals can't refuse treatment, so they must absorb the costs of those who can't pay. That's what opponents of universal healthcare don't seem to comprehend, we *already* pay for all the people who can't pay, we just do it in about the least efficient way possible. Even under ideal circumstances where one has good insurance it's a nightmare. In network, out of network, inpatient, outpatient, specialists, generic and name brand drugs, some stuff is covered, some isn't. You can go see a doctor and not know if you'll walk out with a $30 bill or a $30,000 bill. Doctors will prescribe treatments or medications and it's up to you to figure out if your insurance will cover that particular treatment. Sometimes you have to wait weeks for the insurance to approve it, or they deny coverage on treatment you need and then you have to battle them. It's absurd, and something my friends in other countries always seem baffled by how broken and backwards it all is here.