[ergothus]

That is an incentive to insurers only if they are paying the price or if the lower costs to a specific group of consumers increases their market share. Since most costs are passed on to the consumers and most consumers don't get to pick their insurance (in the U.S.) , the incentives aren't there.

[DenisM]

Employers do pick insurance companies, and cost is a big factor.

[ergothus]

But if the cost is passed on to employees, that cost does not impact the employers.

If said cost applies to only some of the employees, the employer won't have much in the way of even indirect incentives.