Interesting that they compare a 7D with a 6D by price alone. As if price is the only sole criteria by which somebody will choose a camera.
The basic premise of the OP is wrong and he should try shooting the 6D and the 7D side by side, they are as different as apples and oranges.
If this were true, there would be no wait for a 7D Mark II now.
1DX, 5D3, 600D, RX100
16-35L, 24-70L II, 70-200L II, 100-400L, 50L, 85L II, 135L, 24TSE, 40, 100 macro, 18-55 II, 55-250 II, 1.4x III, 2x III, 600RT x 4
The grass is always greener when you crank up the saturation in photoshop