One of the most unfair characteristics of US healthcare is that if the health insurance company does not cover a claim, then the patient is responsible for the payment. It is unrealistic in practice for a patient to know or understand the process by which claims are made (since they are made by an error prone and disinterested provider administrator, and are made in a non-transparent and highly complex way), and also…
And even if you can contest the denial, it can take days to months to get it back, meanwhile you’re shouldered with the burden of paying full price for your treatment with the _hope_ that they’ll reimburse you later. My fiancée has cancer, and we regularly joke that dealing with insurance companies is worse than the actual stage 3 cancer she has. They constantly deny her coverage for medications she’s been on for yea…
Other part of my income was insured by a private company. They lost my files, claimed I didn't fill the forms and after months of fight and involving my employer, they magically found papers I previously sent and paid.
Private companies seek profit and would basically do anything to keep your money. You cannot build a good (fair) insurance company with this logic.