You can say the same thing about professional athletes. Sure, there are bench players in the NBA that would love to start for the Warriors for half of what Steph Curry makes, and they'd probably do a pretty good job. They're amazing basketball players after all. They're likely in the top 1,000 basketball players in the whole world. But they are probably not going to lead the Warriors to a championship. In some situations it's worth paying for that extra little bit of skill+talent.

I'm not sure if that small margin matters for running a major HMO, but I could imagine it does. And that small margin might just be having connections and friends. Maybe having those connections and friends is that extra value proposition that a good CEO brings.