The reason it wasn't flagged is that both the insurer and the provider are incentivized to make this as expensive as possible. Insurers cannot make more than 10% in profit, so if they want to make an extra $1000, they need to take in $10,000. Next, providers are paid fee-for-service, so they want to bill as many services as possible and charge the highest rate for each one. Ultimately our insurance premiums go up to cover this, but the whole thing is a racket.
And single payer will not solve this. All we do is subsidize demand and decrease supply in a never ending fashion in the medical industry. We need to 1) Make it easier to supply services (allow doctors to be imported from other countries, easier to start facilities, allow people with less credentials than an MD to perform services) and 2) Stop subsidizing demand (Medicare for All = Use as much as you want).
My ideal health insurance model is catastrophic insurance provided by the government for any bills over $50,000, Health Savings Accounts to allow you to save for procedures beneath 50k, and a total free-for-all of insurance companies beneath the 50k mark. This would radically reduce insurance rates while preventing people from becoming bankrupt. Catastrophic insurance covers you from cancer and being hit by a bus, but for 99% of all health issues the bill would not exceed that.