You do, it will likely sit closer than PS2 vs Xbox, because the PS2 was below half the specs of the Xbox, but didn't even have the same technological features as the Xbox (more modern shaders that could do stuff that PS2 simply could not.)
Also he says PS4 is a full generation leap, but puts the output of the GPU somewhere at 1.8Tflops, which is half what the HD7970 does today on PCs, and next year will be even slower compared to the HD8970.
There is absolutely no chance of Consoles keeping up with PCs this time, and Wii U's specs seem to point at about half the specs of the Xbox3, which is generally thought to be the most powerful future console.
His speculation has so much riding on subscriptions helping the profits of these next consoles, when only Microsoft has announced something in this regard, and he expects netflix, hulu, hbo, ect to be bundled in the $15 xbox live subscription as if it would be profitable to Microsoft to do that... heck netflix and hulu alone would cost more than $15, so where is the profit?
Basically BG knows some target specs for the PS4, and they are at least 33% faster than Wii U's target specs (which at best are 1.2Tflops, 3 core double threaded IBM chip) AMD of course can't do double threaded cores, and performance wise should be slower per core per hz than a modern CPU from IBM, yet the GPU being targeted at 1.8Tflops is enough for him to declare something like 10x the Xbox360 (which is actually only 7.5x the GPU)
Combined all of this with the fact that budgets won't grow much this next gen from most developers, and you start to wonder if Xbox3 and PS4 won't even use the extra power for anything really noticeable. The only way we will actually see a generational leap is with some sort of GPGPU, which PS4 could have according to rumors, but won't leave Wii U behind anything close to this current gen.