Well you had to way back to prove your point
And I don't believe I need to tell you that the HD5870 was AMD's last GPU that truly gave NVidia a run for it's money. Meaning, that when AMD prioritizes perf/watt, they are more likely to succeed.
Yet they didn't really succeed. Even with HD4xxx,HD5xxx, HD6xxx series, when they were on equal footing and they didn't succeed. Why? Because Nvidia sold more GPUs even with worse performance, price and performance per watt. They had three of a kind. Even now, when AMD is in bad state, strapped for cash, they don't have "dark triade" in GPU market. Worse performance, performance per watt and performance per dollar. Making money on bad chips while your opponent doesn't, will result in current situation where one player in the market just doesn't have enough money in R&D to compete.
My problem is the same as it was with ATi 9800 series. It whopped Nvidia ass. Completely dimantled it. It was on market months before Nvidia, it had better performance in old and current titles and much better in future ones (DX9, Shader 2.0). With AA and AF activated it left FX5800 Ultra in dust, at less price and without heavy factory overclock and gigantic coolers that FX cards came with. I'm not even going to go into details of Nvidia AA/AF implementation at that time (horrid). Just all around ass whopping (lik 8800GT against Ati few years later). But know what happened? People bought more FX cards then ATi 9xxx series. Mental.
What can AMD do about it? When competitor had worse performance, worse perf per watt and worse perf per dollar it outsold them. Now when they have perf per dollar and performance in mid range market, but worse perf per watt, its suddenly huge issue that cannot be overlooked. Even though they have advantages of their own (freesync, CF, better performance in new APIs, more VRAM, less price etc.) its still at disadvantage because it uses 40W more.
What history has shown that AMD even with all around better card and better prices, they still won't get more then 40% of market, let alone 50%+.