Exactly qubit, its a huge factor that people seem to overlook.
Also, take this into consideration. The GTX 580 is about 18-20% faster than a 5870. That means for the 6970 to even compete with the GTX 580, it has to be at least 20% faster than the 5870. For it to be superior to the GTX 580, it needs to be 30-32% faster than the 5870.. do you guys think that's possible... 30-32% faster than the 5870? I sure don't, but I hope so, lol.
Oh, a 30% speedup is certainly possible, even 40% or 50%. The problem is doing it within the constraints of cost and power envelopes and the corporate policies at AMD. Thing is, for the last few years, AMD hasn't really gone for the fastest single chip card crown, instead preferring to make a "high value" card at a lower price point.
What's not helping matters are all these console ported games not requiring the most powerful systems to get the best out of them. For example, my system (see specs) is hardly new, yet runs all my games very well at decent resolutions and image quality settings. So what incentive do I have to upgrade it? Of course, because I'm an enthusiast like others here, I don't actually
need a reason
but you can see the problem on a wider scale.
I think this is a shame, because head to head competition is reduced. The technology then ends up not being pushed as hard as possible. If it had, we would actually end up getting faster products with more features at any particular price point and the top-end products would also be better.
However, it does look like the new AMD high end out soon might compete head to head, so here's crossing fingers!