I think the more common outcome you're not seeing, for the "other" group, is that they just go back to smaller ponds where they excelled in the first place, and often make strong contributions there.

Once it's been observed that there are bigger fish, you can't really go back to the naive sense of boundless potentiality, but you can go back to feeling like a strong and competent leader among people who benefit from and respect what you have.

Your comment focuses on the irrepressibly ambitious few who linger in the upper echelons of jet-setting academia and commerce and politics, trying to find a niche while constantly nagged by threats to their ego (sometimes succeeding, sometimes not), but there's many more Harvard/etc alum who just went back to Omaha or Baltimore or Denver or Burlington and made more or less big things happen there. That road is not so unhealthy or unhappy for them.