In my opinion, money manager selection is a specific skill in and of itself, one that's best left to the professionals--that is, me.
The "strong form" of my self-serving theory states that even brilliant businessmen, or even brilliant money managers themselves, are not necessarily brilliant money manager selectors.
Here is one example: Lakshmi Mittal, a modern Carnegie of the steel industry, lost a lot of money
investing with hedge fund group RAB Capital.
One example does not make a theory, so I'll keep my eye out for others, as well as counterexamples.