I've always thought it was insurance itself that was causing costs to skyrocket.
I was a sick kid growing up, I was always at the doctor or in the hospital, my parents never had any insurance, at that time not many people did.
Cost were kept down because people just didn't have a lot of money to spend on healthcare. My care was relatively expensive but not even close to being catastrophic like it would be today.
As more and more people got insurance the cost of medical care started to grow... and grow.
I think there are a few reasons for that.
#1 If you have insurance you are a lot more likely to want to use it, this was something that really surprised the administration. More people have insurance under obamacare (a whopping 2.7% more)

but also they were USING it. People are running to the doctor for any little scratch or sniffle.
"Oh my god I broke a nail! Good thing my insurance covers emergency room visits!"
#2 People became divorced from the actual costs of their own healthcare. They're not paying for it so they don't care.
Doctor: " Well there is this treatment that has a 0.0001% chance of saving your live, the bad news is it costs $100.000, the good news is your insurance covers it"
Patient: "Fuckin' A doc let's go for it! It's not like it's my money"
#3 Healthcare providers and medical equipment and supply manufacturers saw an opportunity to increase profits because of #1 and #2 above.
I couldn't believe it when I saw on some news show a few years ago that a single bag of saline was around $400.
$400 for fucking salt water
Insurance has driven costs way past the level of service received, all the government regulation and interference in the market has only made it worse.
"Don't worry about what it's going to cost, the government's paying for it"
I believe if all insurance was cancelled tomorrow except a single, relatively low-cost high-deductible catastrophic coverage you would see healthcare costs plummet, People would be paying for all the little stuff out of their pockets and they may be a bit more interested in reducing the unnecessary treatments.
If they had to pay the $400 for the bag of fucking salt water themselves they may shop around a bit for a better deal, promoting competition in the marketplace rather than "Here is your only option sign here" system we enjoy today.
Medical corporations, equipment manufacturers and suppliers would go out of business.
But other more hungry and competitive ones would replace them.
Adapt or die.
This narrative that gets pushed by one of the parties (you guess) that if something happens to your health it's not your fault and it shouldn't effect you at all financially is going to end up bankrupting us all, I have medical issues and I expect to be the one to pay for them.
I'm a type II diabetic with high blood pressure and high cholesterol, all pretty well controlled now thank you.
I don't currently have insurance I looked at the numbers and said no thanks.
I pay for all my own doctor visits
I pay for all my lab work
I pay for all my other tests
I pay for all my medications
I spend less than $1000 per year on my care , obamacare took the low-cost catastrophic option away from me plus wants me to pay $8000 per year (in case Robbie gets pregnant) on top of that they also tax me for not joining up.
Retirement away from the US is looking more and more attractive.