Large swaths of US insurance are underwritten by employers, with the insurance companies acting as contracted administrators. Employers don't have the incentives you list.
What about the other 90% of the country?
I guess Medicare and Medicaid also don't have the incentives. Nor does Tri-care or the VA. My employer self insures as far as I know, and we are a few hundred people. Maybe 90% is a bit off?