Adopting SurfaceFlinger on the desktop would certainly be a step backwards, OEMs effectively fork it each time and change it for functionality on their devices.

Adopting SurfaceFlinger on the desktop would certainly be a step backwards, OEMs effectively fork it each time and change it for functionality on their devices. Google sometimes tries to add these features (e.g. split screen, multiple windows etc) into the base code but can take time for OEMs to adopt them on their skins.