Nope, that's not how it works anymore. First, insurers (payers) no longer even provide much insurance. The majority of their business is now managing networks and processing claims on behalf of self-insured employers.

Second, payer profit margins are now capped by the 80% minimum medical loss ratio introduced by the Affordable Care Act (Obamacare). Payers actually make less profit when they deny care. When coverage for certain services is denied it's usually because your employer designed your plan with strict limits.