I cannot believe you even brought this up. You realize that the gap in power usage between 5870 and GTX480 was
gargantuan?
144W vs. 257W for say an 18% difference in performance at stock. How are you even using this as an example unless you think R9 290X and 780 will have a difference in power usage of 78%?
And BTW I bought 470s and overclocked the hell out of them anyway despite them using way more power than 5850s. It's not that people don't care about power consumption but it's context that matters. 30-40W hasn't killed anyone when spending $600 on a GPU. Again, the very idea that R9 290X will use 30-40W is also completely made up at this point. I just used it as an example for hypothetical reasons and then showed clearly that your motherboard choice alone can negate that. So what now we are going to list every person's rig on this forum and start adding up total power usage?
What's the price of 270 though? What about 270X and 280? One of those could come in at $199-249 and end up with a Tahiti Pro chip. Keep in mind when HD6870 came out, prices of 5850 and 5870 were lower. When older generation is cleared out, you can have some very good bargains. When 4890 came out, it also cost about 50% more than 4870 for a small performance bump.