I think you're right, but also oversimplifying the achievement.
You could also ask, if the 290X offered the same performance as the 7970 who would've bought one of those? The big thing it offered was a performance boost, but Nvidia did that last gen with the Titan and 780 while AMD were still lower the price of the 7970 anx bundling more games to keep competitive.
What would be interesting to see is, if in a parallel world where it was AMDs release that increased efficiency, would the same people still be making the same arguments or would the suddenly be seeing things from the other side because of the brand?
I know everyone will say that they would still have the same opinion, but that's easy to say with no way to test.
Just go back to the 480/5870, all the arguments were exactly the same but in reverse.