In the 1990s, a lot of desktop software was Windows-only, and used the Windows toolkit directly, so they supported the OS theming [1] including high-contrast op

In the 1990s, a lot of desktop software was Windows-only, and used the Windows toolkit directly, so they supported the OS theming [1] including high-contrast options. Windows wasn't alone in providing this. Most desktop operating systems of the day did, including MacOS 8/9, BeOS, OS/2 Warp... Of course, you're right that there never was a utopia of consistency where everything looked and worked the same and always respected user prefs, but the mid to late 90s was about as close as we ever got.