You are over analyzing, gamers don't really care about wattage, most have decent PSUs (I know I do ie Seasonic 850w), they look at price to performance and 480 is up there with the best in that range,
Also don't forget cooling and wattage has dropped for AMD with the 480 for obvious reasons, so is it really even a factor nowadays unless you have a very low wattage PSU, (some would argue if you can afford a decent 480 card ,then you can afford a decent PSU for all your hardware.
I can tell you wattage is not even on my list when I choose between Nvidia and an AMD card, (yes I went XFX RX480 GTR black edition, awesome card

) and that goes for CPU as well regardless of AMD or Intel etc..