So Intel's 4670K is 30% faster than the 3570K and also $30+ dollars cheaper?
This comparison is not as relevant for these reasons:
1) Intel CPUs keep their resale value which means if you buy a $225-325 Intel CPU, you can recoup 60-70% of its value after selling in 2 years. Now look at GTX580 that came out at $499 and 2.5 years later HD7870 is $170 with the same performance, while HD7970 fell from $549 to $280 for 1Ghz versions. If you happen to have a MC near you, then you can buy Intel CPUs, resell them, and lose almost nothing, making Intel CPU ownership extremely cheap.
2) If you do not sell the CPU, i5/i7 overclocked now easily lasts 4-5 years. i7 920 @ 4.0-4.2ghz is still a good gaming CPU. The total cost of ownership per year assuming a resale value of $0 is very low since modern Intel CPUs have a much longer useful life and much lower cost than modern GPUs ($225-325 vs. $650-700 for the GPU!)
3) The nature of the GPU vs. CPU industry. GPUs increase in speed anywhere from 50-100% every 2-3 years, while CPUs do not. Since the GPU cycles are much shorter for major performance increases, 6 months late is a long time in the GPU industry but it is not in the CPU industry where performance increases are very small.
4) Opportunity cost of waiting. If you buy i5/i7, you have an idea of Intel's road-map and it's not as if in 6-9 months Haswell refresh will be 30% faster at $225-325. Now look at the opportunity cost of waiting 6 months and not buying say EVGA GTX780 ACX? It makes no sense to have waited for R9 290X. R9 290X barely beating 780 6 months later for $649 is not an accomplishment, and even worse when it's $650 for a reference cooler. Worse, it's not really putting much downward pricing pressure on NV's 780 since after-market 780s are $650-700 and are 15-20% faster than a reference 780 (Galaxy HOF 780, EVGA Classy).
5) GPU technology curve. As mentioned, the closer we get to 20nm GPUs, the less valuable 28nm GPUs become because we are in the 2nd half of 28nm node generation. Would you have said buying a GTX580 for $450 near the 2 year mark of 40nm generation (480->580) before 28nm 680 launched was worth it? Of course not since you know on the technology curve the 580 was old tech, but the market price has not adjusted. That's what you call market pricing inefficiency. If consumers are paying $450 for a near 2 year old 40nm 580 around December 2011, then they are not knowledgeable of tech cycles. Now imo, $650 for a 28nm card that's only 30-35% faster than HD7970Ghz is way too expensive since we are 2 years into "old" 28nm tech. 28nm tech should be more mature which means a 424mm2 Hawaii should not be 2.3x the cost of a 1Ghz 7970 if it only brings 30-35% more performance.
^ In comparison, HD7970 was $549 and overclocked, it beat HD6970 overclocked by 70-75% when 6970 cost $299. R9 290X offers
half of the performance increase 7970 oc offered over 6970 and costs $100 more.