Narcissus was in love with himself to the point of being oblivious to others. This seems distinct from the flaw of Egotism to me. Egotists are reliant on their dominance, real or imagined, over others. So I think the term is widely misused. The Greeks saw great value in competition and the pursuit of excellence. Narcissus thought he was beyond compare in his perfection. Egotists are like over indulged children but often very conscious of competition. Arrested emotional development and consequent poor socialization, in simple terms.