Insurance is the only industry where customers are the enemy.
The more immediate/pressing your need for risk coverage, the worse it is for them to sell it to you. The less you need it, the better it is for them to sell it to you and the worse for you to buy it.
Pretty different than ice cream or cars or housing. Too many people just think “oh corporate greed” without thinking about the underlying economics (partly because of how us culture pretends markets are magic).
In the past, insurance companies (think: liability, fire, life, shipping) responded to a claim by hiring a lawyer and negotiating down. Like most contracts.
So states began creating insurance commissions, which serve as law firms that defend consumers from insurance companies. In practice, their existence forces insurance companies to pay what they are owed.
We need insurance commissions for health insurance. If there is a reason why the policy shouldn't pay (services received after policy expired, for example), the insurance commission has to sign off.
This is how normal insurance works. Health insurance, of course, is not normal insurance.