The 1070 and the 970 are vastly different. The 1070 doesn't enjoy the same superiority over the 980ti that the 970 did over the 780ti.I don't think it will sell as well as the 970 did for a few reasons. Firstly the 970 when overclocked was very competitive with the 980, which was widely considered overpriced. This time they have be careful to demarcate the 1070 much more from the 1080. Secondly the entire line has crept up in price to the point it might alienate some value buyers. I'm not saying that this card will tank sales wise but I wouldn't be surprised if the 960 replacement (which was second if you consider Steam data useful) is a better seller this generation. Thirdly I think people are getting more savvy to the fact that big Pascal is around the corner and what that will mean to the relative performance of these cards. We will see though, happy to be wrong.
"Can easily afford" doesn't mean wishes to spend. This adult could buy whatever card he wishes but I've always set myself a budget and the 1070 at least currently is outside it. Still interested in the technology (probably more so than gaming tbh) if you're wondering why I'd be reading reviews.
Compared to the 970/980 launch the 1070/1080 launch is far far worse. Especially when you consider 2 node shrinks and a new architecture.
Also @happymedium
You say adults can easily affordable these cards yet do you currently own something faster than a 970/290 even?
Most gamers refuse to spend money on hardware. They like games not purchasing new gpus.