In my experience, perfectionism is a reaction to a lack of actual progress or success. Kind of similar to forms of idealism or religious feelings that arise as a result of being powerless in the face of circumstances.
it explains why many scientists are self-denying and perfectionistic: failure is the rule during experimentation, and progress is not guaranteed or even knowable sometimes.
i think that eventually it gets inseparable from the person. the reaction becomes a habit, and then it sticks.