Having more diverse editors will lead to more diverse content.
Wikipedia pages of female scientists tend to get a lot more scrutiny than ones about male scientists [1].
There's another anecdote about moderator bias and some decent discussion on the issue overall in this thread [2].
Ultimately there are some issues Wikipedia can't solve since they are just a reflection of the rest of society in many ways.
"We can't write about this scientist and her work because no one else has written about her," is a problem that Wikipedia can't solve by themselves.
[1] https://www.chemistryworld.com/news/female-scientists-pages-...
[2] https://old.reddit.com/r/TwoXChromosomes/comments/ekv3te/fem...
Can you elaborate what content you'd expect to see more of if the editors were "more diverse"? This gets thrown around a lot here, but nobody actually says what exactly they mean. There are more than six million articles on the English Wikipedia.
What would change, which topics would get more, which would get less attention if Wikipedia editors were swapped out to represent their attributed groups (along some axes; most likely gender and broad ethnicity, I'm guessing, but not social status or education) of the American society at large?
If there were more Norweigan editors then I'd expect to see more content about things that are "notable" within Norweigan history and culture.
Replace Norweigan with African American, female, etc. and you'll see how having more diverse editors would lead to more diverse content.