I recently discovered MonitorControl[0], which is a Mac app that listens to your default brightness and volume keys and pushes updates to all connected monitors over DDC. Extremely happy with it.
I'll quote an HN discussion from a few weeks ago on why this isn't more prevalent.
>There is a problem with "cheap" monitors and DDC/CI: some of them use EEPROMs to store brightness settings, and this limits you to about 100,000 writes.
Worrying about this is the main reason we don't ship DDC/CI with f.lux. (I know that some more modern monitors use NAND and don't have limitations like this.)
>There is a problem with "cheap" monitors and DDC/CI: some of them use EEPROMs to store brightness settings, and this limits you to about 100,000 writes. Worrying about this is the main reason we don't ship DDC/CI with f.lux. (I know that some more modern monitors use NAND and don't have limitations like this.)
https://news.ycombinator.com/item?id=24344696