People are cut out for different things. You have "brave" teachers, and you have "brave" managers. We all recognize them, but don't appreciate them as people enough, even when these breeds are rare gems.

Even for someone shy, with experience and hard work, one might end up becoming a death-defying samurai.

What the text doesn't recognize is that many people just don't feel all that much or have that much empathy. So there's less of a spur to actually do the work to become a natural leader or go into enough depth.

I don't think that's the case, since Matt Cutts kinda had the same role in Google before joining USDS. Or maybe he's gotten used to unexceptional employees there.