If you have health insurance, and you keep your health insurance through whatever your medical emergency is, you won't have a financial problem with regards to medical bills. I'm splitting this up into two parts: how it works, and why that's the wrong question to ask.

Here's the nitty gritty. Health insurance will cover each expense minus a deductible. Once all your individual deductibles have reached a set value called an "out of pocket maximum", health insurance covers 100% of it. So if your deductible is $200 and your out of pocket maximum is $2,000, and you have a serious medical problem that requires multiple hospitalizations, you'll pay $200 up to a maximum of ten times, at which point every hospital trip is free for you. If your out of pocket maximum is $2,000, you don't have to pay more than $2,000 for healthcare in a year.

Here's why that doesn't matter. It's too easy to lose your insurance. If you buy health insurance directly, and you miss a payment, and you are an expensive client to your health insurer, your insurer will drop you. If you get your health insurance from your employer, (which is a majority of insured people in the US) chances are pretty good that an expensive medical emergency will coincide with losing your job- which means your health insurance changes. There are systems in place to deal with this, but these systems suck. There are a lot of cracks you might slip through while transitioning from your employer provided insurance to whatever you transition to.

Literally everybody loses with this system. Insurance companies have it the least bad, but health insurance companies aren't actually that profitable. Doctors can open their own practices and "set" their own prices, but insurance companies can and do ignore those prices. There's this weird nonsense where providers (hospitals and independent doctors) set prices, and insurers pay a percentage of those prices, so providers raise the prices quoted to insurers... so insurers lower the percentage. This is why you hear stories about people receiving ridiculously expensive bills for short/trivial hospital stays. The cost to the hospital might be $2,000, so the hospital quotes the health insurance company $50,000 with the expectation that the insurance company is going to write a check for 2.5% of that or $2,500. But the patient is uninsured and gets the $50,000 bill instead. If you're familiar with the system, you can haggle with the hospital and they'll be happy to accept $2,500 from you, but that's only if you're familiar with the bullshit system- most people obviously aren't. When you hear complaints about the 'lack of price transparency' this is one of the many ways that is presented.

It is the worst of all possible systems. If the government literally repealed every law and regulation with regards to healthcare, that would be a less awful system. Significant change, whether that means going full socialism or full lassez faire free market, would require a filibuster proof majority. (60 votes in the Senate) Many politicians who want to improve the system would not be keen on voting in a half measure; for instance, breaking the link between employment and health insurance would be a huge benefit to all Americans, but it's a political loser for Democrats. So there's insufficient support for dramatic measures, (because people are either strongly opposed to socializing everything or they're strongly opposed to deregulating) and there's insufficient support for small improvements. (because if the system were less intolerable they wouldn't be able to run on a platform of significant change) It's bigger than just a problem with healthcare; it's a problem with the two party system.

https://www.healthcare.gov/glossary/out-of-pocket-maximum-li...

https://www.healthcare.gov/glossary/deductible/