We have already seen it with things like Medicare Advantage plans doing sign-up meetings on the second floor of buildings without elevators etc.
If you want to look at them done correctly, look at the FEP program. High-level KPIs that are difficult to game (without actually improving service & outcomes) tied to financial incentivizes.
Generally speaking, you get decent outcomes with {not for profit} + {efficiency/outcome based KPI}, because the primary thing you're fighting is apathy (not for profit) instead of malicious profiteering (for profit).
And capitalism doesn't particular lend itself to running an insurance company. Fundamentally, there's not that much that should change year-to-year at insurers than {actuaries / pricing}.
Have pharmacy benefits or all the other kooky for-profit inventions really improved patient experience and outcomes?