That being that black paper is more expensive than white and that we're stuck with historical precedence?

Reading white text on a black background is much, much easier for me, and the few times I've had the pleasure of doing the same with paper, I still found it to be better. I haven't tried longer texts, since nobody's publishing actual books with black paper, but I'm willing to bet it I'd feel the same about those.

This just reads to me the 'serifs are important because they make reading easier (when reading of paper)', which doesn't reflect my lived experience at all. The only reason these phenomena seem to exist are historical accident and people being used to them.

Because wood is bright and you can’t really print white ink on a black paper?

There might be a usability advantage but using black ink on white paper doesn’t really prove that, that’s just the easier option of the two possible choices.

Apple soon started offering a dark mode as an accessibility feature https://kalleboo.com/linked/mac_closeview_control_panel.png