a minority of individuals sees power as an end in itself, while a majority see mutual support as an end in itself
That minority of power individuals looks pretty cooperative among themselves, while the majority does actually very little for mutual support. How much of their effort is not directed towards minute needs of themselves or serving the power minority? There seems to be little confidence that doing good to others is reasonable.
Dan Ariely's book, Predictably Irrational, among its other virtues, describes experimental behavioral economics results that reveal the fragility of social norms when these are forced into competition with market norms. It's a fascinating and sometimes profoundly disturbing book. I highly recommend it, even to those who have been casually following the literature in the area. (Fun to read, too.) Words and ideas I offer here may be used freely and without attribution.