Try leaving the Apple bubble. Windows 95 had completely tunable color schemes and fonts. Even Windows 3 was highly configurable. That configurability went away with the rise of the web and the death of native GUIs, to the point that Microsoft didn't even bother making the native toolkit configurable at all in Aero.

We could tune up our own universally applied dark mode in 95 quite simply, but now each application has to implement that itself.