It only really works for bootstrapped non-profits, and for projects that are entirely volunteer-driven. No VC would be able to invest in something like this (unless it's a grant like what YC does for non-profits [1]).

Even Mozilla Foundation [2] was spun off from Netscape, and heavily supported by AOL in its early years.

[1] https://www.effectivealtruism.org/articles/why-nonprofits-sh...

[2] https://en.wikipedia.org/wiki/Mozilla_Foundation#History