No, no, no. Don't take all those for real. They measure the entire board that is different from smartphone boards. My personal tests only with a cpu say this: A9-single (13m transistor) @2ghz 65nm-HP =950mWp. The same at 45nm-HP =500mWp, and 40nm-LP =350mWp. The same at 28nm-LPE =200mWp, and for dual core 400mWp. If we assume that an A15 consumes 2x as it is, and 3x with the 32nm-Samsung, then 2.5Wp for the entire SOC with graphics and without memory its fine. For example the dual A15 inside the new iPhone what do you thing it consumes? If it was 5Wp without memory then the device will power off in 15 minutes full use.
Iphone has a 6whr battery, that can last for one hour if soc+screen power is 6w.