"Find or make a niche" is not a strategy someone can automatically pull off when they hit a certain level of rationality. That someone has not successfully done so does not mean they are irrational. Your original comment implies (basically states) that someone who is not getting anything done is, QED, not rational. This is nonsense for the same reason.

You are proposing solutions for which rationality is not the sole determiner of success. people can fail for reasons other than irrationality. Emblematic example of the just world fallacy, with justice here being "rational people succeed."