I even use it for the network-based DDC in Lunar through a Raspberry Pi when wire-DDC from the Mac is not available: https://alinpanaitiu.com/blog/journey-to-ddc-on-m1-macs/#the...
Well it kinda is up to the monitor. Given how many monitors don’t implement the DDC/CI standard correctly and flash and crash and blackout on simple brightness change commands, it would turn into a PR nightmare at the scale of an operating system.
I’m overwhelmed by the daily support I have to provide for Lunar users and I barely have 20k users. I can’t even imagine how bad it would be if 100k users started having their monitor crash or lose color on “such a simple thing as changing brightness”.