What the WMF does do at times is fund community "organizers" trying to get unpaid volunteer editors to work on its content. See e.g.:
https://diff.wikimedia.org/2022/09/22/join-the-organizer-lab...
Direct editing paid for by the Foundation was tried once, with bad results:
https://thewikipedian.net/2014/04/02/bats-in-the-belfer-a-be...
I guess what I was thinking more of was philanthropic organizations paying mathematicians, geologists, and various other types of academic to improve the quality of Wikipedia's entries on a full time basis. Maybe I am being hopefully naive about the allocation of capital though, and thinking merely the sort of things I'd like to fund if I were a billionaire.. ;-)