Some loaves of bread are worth a dollar. Some are worth ten dollars. The exact line is hard to pin down... but a $1,000 loaf of bread is probably excessive.
One part "free market -- maximize your profits as much as you can and get rewarded by a skyrocketing share price!"
And one part, unspoken except in the PR BS put out by the insurance companies, "Try to improve the health of patients and have them not die!"
The only way the two can coexist at all is if someone draws some lines like you are suggesting. I know that there are some (probably easily manipulated) laws stating that X% of premiums have to be "spent on care" and if they get too high overall margins on your group, they have to give your employer a rebate. Of course, who knows whether you'll see that money.
If we just say "maximize your profits" (and indeed, shareholders 'should' sue them if they don't) then it's obvious that morally bankrupt scum that runs all these insurers would 100% extort people for 1000% profits on lifesaving drugs. It's the most logical course of action! People will pay infinity dollars to save their own lives/their loved ones, so let's soak them!
If it's not obvious, I believe that overall the "free market" part of this system is a failed experiment that should be abolished immediately, and not just because I want all of these companies' sickening, greedy executives to go straight to hell (where Brian Thompson is burning today).
A better approach would be to mandate that everyone purchase individual or family policies directly from insurers on open exchanges using pre-tax dollars, with subsidies for low-income consumers.
after WW2, there was very obviously inflation. It was crazy in the EU and Japan, but the US still experienced some too. To fight this, the government made a then-common tactic of wage controls: basically cap off the maximum amount an employer can compensate workers, in order to fight the inflation spiral.
But there was an imporant exemption. This was only on wages and not any benefits given to employees in order to try and quell the inevitably angry employees. So when companies couldn't attract talent with more money, they offered more benefits. including employer sponsored healthcare. Perfect since these contributions were free from income tax.
And the modeled spiraled from there. a tax code passed in 1954 to let these contributions be business expenses, Medicaid came in the 60's, etc. It was great back then, but it was getting more expensive to navigate and companies started compromising to manage it. up to our favorite healthcare starting its vertical integration 20 years ago to come into what we know them for today.