I see it different. I think there are "me" people and "we" people. Me people are centrally focused on themselves and their own. We people think about others and the totality vice just their personal interest. I think we are ALL born as "me" thinkers and those who are ready evolve into "we" thinkers. To me this is the barrier we must cross as a species to reach our most optimum abilities as humans. We work better as a goal-oriented group than as self-satisfying individuals. Like the starlings flying in those amazing large groups that all turn the same way. They aren't psychically linked ... they just all think the same way and are cued by the same stimuli.
I don't know how accurate your theory is but it sounds right to me, especially as it applies to people I have known. Very glad to be able to count myself among the evolved.