The reason is simple, for profit healthcare, simple as that.
In my area I am old enough to remember when all hospitals where I live where run by various charities. My small city of 100,000 people we had 3 hospitals. 2 run by Roman Catholics and a third was non-profit. Back then things were kind of cheap when compared to what people's salaries were.
Now there is only 1, owned by Tufts. The non-profits were pretty much eliminated in the late 80s or early 90s, and no one can pay their hospital bill without insurance. Even with insurance it is very hard to pay up.
So there is your answer :)