At least in the US, the ACA recalibrated how insurance companies get re-imbursed. Their margains are set as a percentage of the payment that goes to direct care. If the prices go up and their margin ratio is fixed, then it is in their best interest for charges to go as high as possible. Same as everyone else in the supply chain. Everyone is suddenly making money hand over fist and the insured can't say no to the premiums.

https://www.moneygeek.com/insurance/health/aca-medical-loss-...