I don't understand your point. Technology improves over time, and it's reasonable to expect that Apple will create an even smaller laptop with a Retina display which it might call a "Macbook Air."
Not so much in battery tech. It's really holding back a lot of hardware innovation on computers and also holding back the viability of EVs for many consumers.
The Retina display in iPad Air is much more power efficient compared to the retina display in 3rd gen iPad due to reduction of backlight LEDs and move to IGZO type of panel.