Anyone doing well in life is a rationalist in the sense we use it on LW?
No, but that wasn't what we were talking about. They could have been lucky, but then their success didn't come about because rationality helped them win at life. You're saying a better rationalist will lose more often than a worse rationalist, which is wrong by definition since rationality is the art of accomplishing one's goals effectively.
Related to: Knowing About Biases Can Hurt People
HT: Marginal Revolution
Paper.