Shawn,
Your questions presuppose that profit motive is necessary for the
perpetuation of social systems. But profit motive is a characteristic of
only some sorts of social systems, and these are marked by extreme
inequalities and social injustices. The answer to your question is
answered by asking another question: how did other societies get along
without the profit motive?
The other false assumption in your argument concerns incentive. Where is
the incentive for workers to work hard when they do not take profits? Why
wouldn't a system in which workers were rewarded the full value of their
efforts be an incentive society? Seems to me that such a system has more
incentive to be efficient and productive.
Under capitalist relations, profit taking is an incentive to exploit labor
and ecosystems. This is not the behavior a just society should reward.
Andy