You seem unable to grasp that future games are still not going to need a new CPU except in extreme situations. (A 1600 Sempron or 3.0GHz P4)
Lets say that you've got a Pentium D rig at 4.2Ghz with an 8800gtx and it's capable of playing current games at ~120FPS @ 800x600 resolution. Most people would be SCREAMING at you to change your CPU. Your max FPS is 120 solely because your CPU is bottlenecking your GPU as pictured here.
However, your monitor is still holding it up at 60FPS regardless of what the other two can put out.
You'll notice AT NO POINT WILL THE CPU BECOME THE BOTTLENECK. Now, lets assume that the next games will want to run FOUR threads that are all equally as hard to run as the current one (as far cry to how it really will be). But now you have two cores to take advantage of, so... it doubles the processing power and quadruples the load for a net effect of half the frames per second. It now looks like this...
The CPU is STILL not the bottleneck, the monitor is.
Now, really, no new game will quadruple the CPU load. Though they might double the GPU load. That's feasible. Lets look at both situations then.
Well, now the GPU has become even MORE necessary and even MORE pressing than the CPU .... and that's compared to how important it already was. This makes my case EVEN BETTER, you need another GPU or to OC your GPU to keep your GPU from becoming the bottleneck. STILL NOT YOUR CPU! What's my point even BETTER? Dx10 is offloading more work onto the GPU making it an even BIGGER bottleneck.