Not defending the blocking of rooted devices, but I think it's excellent that airlines are relying on people bringing their own hardware. I think you'd struggle to find a single person in an airport who isn't carrying a screen with them today, so seat-back screens feel very redundant to me.
They aren't doing it to be green, they are doing it to save money on chair replacements. I'm surprised how rare it is even to get a seat with power hookups these days. Even in the actual airport itself plugs are still relatively rare and closely guarded, actual functioning plugs rarer still. I remember when economy meant a new set of headphones and the billboard top 20 playing from the arm rest.
As a person who carries a 5.4" iPhone 12 mini, please keep seat-back screens. I wouldn't mind if they were just HDMI-devices I can extend my devices screen to though, that would be amazing!
