The usual reasons: corruption, fraud, graft, defraying the cost of free medical for illegals and deadbeats.
I have an acquaintance that invented a medical device. It is staggering just how much money there is in medical supplies, treatments, etc. And that is even AFTER paying ludicrous malpractice insurance rates, etc.
There are some incredibly lame reasons why it costs $50-$100 per hour for things like a plumber, mechanic, etc. But an hour in an operating room can cost tens or hundreds of thousands of dollars. I suspect the whole thing will need to collapse in a way, and be rebuilt.
Just as it used to seem reasonable to pay $1200 for a CD player in a world where the average person made $25,000 a year, and then $35 was too much, I suspect we are coming to a day where paying more than a few hundred for a hip replacement will seem ridiculous. But first, the existing paradigm will have to collapse. And it will not do it voluntarily. It will have no choice if it wishes to survive.