Social enterprise (aka revenue generating activities -- an area in which BWB Solutions has extensive experience) can play a role to achieving sustainability but first, this is not a panacea especially for nonprofits in crisis; second, the selected venture does best when related to mission (I'm not 100% in agreement); third, there must be a defined market/demand (ABSOLUTELY); fourth, there needs to be some internal capacity to do this.
From one study on the matter, there appears to be a preponderance of ventures at the small and large end of nonprofits but not much in the middle. Hm....
Social Impact Bonds will likely have some impact on all of the way nonprofits can finance themselves in meeting social needs but this may take time -- the long range strategist though should be thinking about this source...