A more power efficient gpu is also easier to overclock and requires less expensive cooling solutions. ever wondered why the Fury X requires water cooling?
As i said before Nvidias 900 and their current 1000 series are simply better than the AMD cards and I am pretty sure the sales figures would also support my claims.
It wasn't until the release of the much more efficient rx 400 series that AMD managed to gain some market share:
Don't forget that even AMD themselves used the GTX 1080 when they showed off their Ryzen 7 1800x...
I was never arguing that Nvidea cards aren't better (I'm using 2 of them, remember?), my point is that they're not that far behind Nvidea for equal generations/pricing and I don't see it outside the realm of possibility for them to come out with something nearly as good as the 1080 Ti for less money. I doubt it'll happen this year though.