Maybe, if their MacBook Pros were just a little bit thicker (say, the thickness of the 2013-2015 models), they'd be able to fit a big enough battery for the extra power draw to not matter too much?
"Considering that a 76 watt-hour battery is used in the 15 inch machines, they could have made the battery 30% bigger to hit the ceiling imposed by the Federal Aviation Administration, and they still wouldn’t have had the same battery life as they do now by using LPDDR memory." [1]
