The health insurance companies have been allowed to operate much like public utilities and had no incentive to control cost. Due to regulations they have been forced to provide certain levels of coverage and then allowed to recoup cost times x. This model has made it profitable to accept higher cost because X percent of 100 billion is more than X percent of 50 billion.
Before the ACA, I actually had a fairly efficient model. I could buy a really good catastrophic plan with a max 10K per yr out of pocket. Sure, I would pay my family doc a couple of hundred for my annual physical or a sick visit but I was covered for a major illness. Today, I'm forced into a 2K per month premium with 3500.00 deductible. It's not the doctors, hospitals or big pharma that screwed up my policy.