The ACA tried to address this sort of thing with a Medical Loss Ratio [1]. This basically meant that 80% of premiums had to be spent on healthcare. This has two obvious flaws:

1. Certain government contracts are what are called "cost plus" contracts. These have the same flaw. If the contractor earns 20% above "costs", they're incentivized for a cost blowout. Same with insurance premiums. If you have $100B in premiums, then $20B doesn't have to be spent on healthcare. But if premiums were $1T, then that same ratio is $200B. It incentivizes insurers to raise premiums; and

2. Health insurers cheat on the ratio by moving profits elsewhere. For example, UHC has a pharamaceutical benefits manager ("PBM"). Sounds inocuous but it's evil. PBMs bulk negotiate with drug suppliers but can basically keep the volume discount as an extra profit. PBMs do much more such as constantly force what medications are covered to force people to ssee providers even and get a prescription for whatever the new medication is even if they're stable on current medications. The whole point is to make people give up (or die).

But health insurance companies also own providers like hospitals and medical providers, either directly or through thinlyhh veiled subsidiaries meant to hide profits and that corporations are making healthcare decisions (something certain states have laws against).

The whole thing is a ridiculous system and needs to be scrapped.

[1]: https://www.cms.gov/marketplace/private-health-insurance/med...