Effectively, it's a fact : peoples expect more CPU performance for a lower power consumption.
It may due to the industry's ads : always more XX% of performance gain and less XX% of power consumption comparing to previous model or competitors (look at the recent Apple keynote about A13 SoC - could be applied to every manufacturer's keynote, though).
We also have to consider that devices embedding those SoC are idling most of the time. Smartphones, tablets or whatever mostly uses smaller process SoC, with big.LITTLE cores, and a good power management and I think we have an answer explaining why peoples are expecting more (announced) processing power for less or equivalent power consumption.
Idling at low temperatures globally helps a lot. I think it's the key point.
It helps for user's feeling of having a good overall system temperature (totally subjective, though).
More technically, it helps to offer a better inertia to prevent throttling, idealy before the power hungry task is finished.