alt Hacker NewsSome nonprofits do run largely off endowments.
One big issue is that it's a PR problem; most people don't really understand it. They'll look at the non-profit and say "why does that need to raise money, it's rich". You saw this a lot with Harvard in Trump's recent funding war with it, say.
And the biggest expense of the most successful charities is fund raising. It's a viscous cycle and when Watsi came along they showed maybe an alternative path.