They exist? This is called FOSS and some outfits are even able to offer paid employment.
One can imagine trusts devoted to open source. (They probably exist in some form.) But that probably means that modest amounts of money are distributed to a vanishingly small number of coders based on, likely, the preferences of some executive director.
In general, it's fairly clear that jobs for open source developers is generally more effective than charity of various kinds which is subject to change at any time. (OK, jobs are too but that tends to be less related to political, etc. winds.)
FOSS is not a monetary instrument?
A commit bit may not be liquid, but you can earn from it. There’s tons of companies that would pay for prioritization of their desired FOSS work.