16nm A72 has about twice the performance of a 20nm Cortex-A57, and consumes about half the power.
"We have a strict power budget; this is a fanless design,"
And this is the thinking that caught Intel napping after a very large meal. Do much much more, with much much less.
ARM is the British tech success version of Apple, not the richest company in the world by virtue it doesn't manufacture anything but almost everyone in the world owns an ARM designed component. Announcements should be made from Blighty first and then pop over the water to say the same thing but with slightly more fan fare and cheerleaders.