Still, my question remains - is there real data out there to support the contention that P(elite career|IQ) has a local max and then decreases for higher IQ?

No. As I point out in my comment there, the evidence is strongly the other way: TIP/SMPY. To the extent that measures like wealth hit diminishing returns or even fall (eg Zagorsky), it has as much to do with personal choices & values as ability: the physicist who could make money on Wall Street but chooses to continue studying particles, the person who chooses to become an influential but poor writer, etc. (There are many coins of the realm, and greenbacks are but one.)