What do you think happens when a company has limited margins? Hint: almost all companies try to make a profit (which is fine). If the margins are unrestricted, the company can cut costs to increase profit, which is a good thing. If the margins are limited, the company must raise revenue to increase profit. For an insurance company (or a utility, and California has exactly the same broken rule for private utilities), this means raising rates or premiums.
It gets worse. If an insurer raises rates, they are required to spend 80% of that money! They are required to be inefficient! If the insurer reduces their outflows by 5% by doing a good job, they lose 5% of their profits by law. So they are basically required to do a bad job.