Do you have the benchmarks to show them getting significantly better performance? In contrast, the GTX 980 ti is a singe tier above the GTX 780 ti and GTX 980. It provides 20%-30% better performance in most games. Some of the other GPU tiers seem to show about a 10%-15% performance improvement.
For Dragon Age Inquisition-one of the newest and most demanding games, the difference between an i5 3470 and an i7 5960x is about 6%. Even that difference will be impossible to see because in order to show the difference you have to turn down the settings to the point where the game runs much faster than any monitor can display.
The newer/better CPUs are faster, but they just don't make much difference for gaming except in a few edge cases. I think that the current chart encourages people to be sensible with where they spend their money. Jumping a tier or two in GPUs will make a difference. I think it should be the same with CPUs.