In the for-profit world, people raise funding (or take out a big loan), build their thing, sell their thing, and eventually make money (or fail).
In the charity world, there is no seed funding and no hope of future profit, so you raise a little, do a little, raise a little, do a little, raise a little, do a little, and wash rinse repeat that for the rest of your life.
Start-ups may bootstrap, but only because they expect to turn a profit some day. Charities basically bootstrap in perpetuity, and they do it seeking to solve the most complex problems of our time.
Having been in the charity sector my whole adult life, the notion of starting a project with even a decent fraction of the capital you need to build and launch it, is mind-blowingly foreign.