The Essence of Nonprofits?

Nonprofit Assistance Fund in MN lends money to nonprofits. In recent posts NAF has reflected thoughtfully on emerging trends in philanthrocapitalism and what the "essence" of a nonprofit might be.  Maybe the essence is that human beings are social creatures for whom certain social virtues like kindness come naturally (along with vices like greed, hypocrisy, spiritual pride,  and lust for power). Perhaps the unique thing about the nonprofit world (including the arts and private acts of generosity among family, friends, and neighbors) is that public goods lag private goods in a hyper-capitalist economy and that some people will indeed make significant sacrifices of time, money, and ability, or of blood, or even of their own life, for a cause that they consider noble. Perhaps you could get towards an essence if you started from public goods, honor, and an ethic of stewardship. I have not seen so much of that ethos of good stewardship in the business sector, or in government recently.  If the  double bottom in social entrepreneurship line means stewardship, even at net personal cost, I applaud it. But I think social entrepreneurs want, generally, to have it both ways - do good and make out like a bandit. And I am afraid that leaves many worthy projects that do require sacrifice on behalf of others as the province of the nonprofit form or of taxation and government programs.