"Even for us, though, we can often increase our impact a lot by improving our generalized effectiveness."

This rings of Scott Adams' 'Talent Stack'. He posits that having expertise in multiple, unrelated fields both expands your generalized knowledge and helps you stand out in the combination of talents you possess. One example of a real person is one who holds expertise in artistry (oil painting), mechanical engineering, and cycling.

If I were to claim my own, it would be program management, poker and music.