Hospitals don't compete for your business. As a general rule, you don't even think about which hospital you are going to when you get sick or injured. In many events, you aren't even conscious to make such a decision.
Therefore, hospitals are given to believe that they are able to demand any amount of payment they wish. If they had to compete for your dollars, they would have to place limits on how much they charged. The lack of competition, however, means that they can basically charge whatever they feel like.
Insurance companies often oppose many of the charges that are incorporated on the hospital bill. Even personal doctors often attempt to impose charges unnecessarily, and insurance companies look warily for extraneous surcharges that are inconsistant with the needed treatment.
Unfortunately, when insurance companies refuse to pay, the bills do not go away. They return to haunt the person to whom services were rendered. Taking it to the courts cost even more money, so most people are simply stuck.
I am not sure exactly how to remedy such an outlandish situation. I only can say that it needs to be remedied. Perhaps there should be a way to "shop around" for hospital services, with an ID tag stating what hospital that you wish to go to should the need arise. You could wear it around your neck in case you are unconscious at the time. It would take a little effort, but would cause a sort of competitive environment that could bring down hospital cost a little.
It would be a start. Maybe.
I am become death, destroyer of worlds