The medical "system"

I was at a doctor's office. He has a handout for his patients. It points out that if the patient has insurance the patient is the consumer of the insuror's product.

If I am a consumer of medical insurance then why is the system so messed up? Shouldn't market forces work to keep things in balance?

Here is one flaw in Medical legislation in the US. Most employers have tax incentives to provide medical insurance. I as an employee cannot easily afford to ignore this benefit and choose the insurance company that works best for me. Or to dump my company's insurance if they screw up or if they offend me, or if they start supporting some cause I find idiotic. I.E. I stick with them even though I would rather try another company. And they know this.