One hates to be a pedant, but that's not strictly true. 501(c)(3) charities are also incorporated as are a whole range of government sponsored enterprises, local governments, and other organisations that are not about making profits.
Despite the name 501(c)(3), exempt Non-Profits are also about making...profits. It is a giant misconception that non-profits can not make profits, but the reality is that many do make profits. The difference with the non-profit is that there are no shareholders (owners)so profits are not distributed to anyone, instead the profits sit in the 501(c)(3) bank account until they are used.
Also, local and municipal governments are not eligible for 501(c)(3) exemption, they may obtain tax exempt status, as you reference, but it is under different section of the IRS Code.
True, but they are still out to make a profit, it goes without saying that if they do not at least generate enough revenue for expenses they can not continue to exist at that rate in perpetuity - but the reality is profit is required to create Trusts to pay pre-existing liabilities such as bonds and pensions, not just cover overhead - in fact we are seeing major cities file bankruptcy setting new precedent in bankruptcy law. See, http://articles.chicagotribune.com/2013-03-31/news/sns-rt-us...
I can not help but like your spelling of organised with an "s", I think I am dropping the "z" and using "s" from now on. Wish I could give a 2nd +1 just for that.