I have been with such a person and I can tell you the cognitive dissonance of that life weighed on them and made them generally unpleasant in many ways.

They can, yes. The question is, however, what their natural behaviour is. Are they generally nice people and act like jerks just to get ahead? Or are they jerks and need to keep it together with family, friends, etc? Either way, in one part of their life they need to behave against their nature.