That's because, if the chip uses 20% less power, if the latest Soc performs the same as last year but consumes 1w less power no one will buy it. So Qualcomm has to increase its power limits to show graphs like 50% FASTER WITH SIMILAR POWER CONSUMPTION
Personal anecdote:
the lower end chips like SD695 and SD732 have amazing battery lives. I personally use a SD732G smartphone with a 6000MAH battery and it gives me amazing 3-4 days of battery on one full charge