Windows distressingly has two completely different mechanisms and APIs for setting brightness: one that operates over DDC/CI, and another that does something else (I’ll call it Method B, not knowing a better name). External monitors use DDC/CI, internal monitors (mostly meaning laptop screens) use Method B. I have failed in any attempts to hook brightness keys in user space (like how on Linux you’d just intercept XF86BrightnessUp and XF86BrightnessDown); something steals those keys before they ever get to user space, and use Method B. And there is no user interface anywhere for DDC/CI adjustment: it’s only an API that you can call.

So the end result is that Windows users can’t adjust the brightness of their non-laptop monitors without third-party software, or reaching around the side of the screen and fiddling with the infuriating controls of the frustrating OSD interface. So almost no one ever adjusts their screen’s brightness at all, and almost no one of the remainder adjust their screen’s brightness to match conditions. And manufacturers have (understandably) decided that too dim is worse than too bright. So most people’s screens are genuinely painfully bright. So then people say “don’t use actual white” and “don’t use actual black”. And those that have calibrated displays end up sad.