He never said it wouldn't run on a 7970... The title is very misleading. They said last year it took 3 nvidia GPUs to run the Samaritan demo, but now it only takes 1 kepler. The only mention of delaying the engine is for next gen consoles, which will feature a low end AMD GPU 7 series, so....
The title is very misleading. I remember seeing data on the Tflops needed for the Unreal 4 engine and current video cards were more than enough to handle it.