You're committing the same mistake that is expressly argued against in the story. The story is directly criticises rationality taken too far; it's advocating a triumph of will to achieve. Who are you to say that the mission is more likely to fail without someone with that will to succeed, and instead with yet another rationalist who will lose hope when their models tell them it won't work out? Who will give up the swim when they see no way back to shore?

Teams generally work better with a mix of different people, rather than uniformity. I'd be willing to bet that if the scenario was real, the mix would work better.