I think you are taking this way to serious now. All I said is this - RESTRICTIONS (die space, watts, law regulations etc.) are the SAME for both companies. NEEDS are NOT the SAME for both companies. Sony's aims for simple and powerful GAMING box first, while MS seems to be aiming at MULTIMEDIA first and GAMING later box.
One will go for more RAM in console because thats what they need, even though its slower and doesn't compare to GDDR5 when it comes to gaming. Other has gone with less memory but one that is faster. They won't be able to dedicate much to multimedia in comparison, but their goal was obviously gaming.
And thats why I said, they picked up downclocked Pitcairn GPU (that and 7770 are great candidates for consoles), paired it with 4GB of GDDR5 and called it a day. Its simple, powerful and gaming centric. No body ever said 7850 was impossible, you are to emotional and it clouds your thought process. 7850 was the GPU first said to be in PS4 year ago. Actually, everything we heard today was already known a year ago, except for more RAM (and then it said if densities allow) and dropping 4 core CPU in for 8 core smaller one.
Having 8GB of slow RAM, 8 core CPU from the start that seems to be modified and new Kinect that can turn on your car from couch is not what I would call gaming centric. In the end, both companies will spend similar amount of transistors on their console, they will consume similar amount of watts and the only difference will be companies goal, which seems to be very different as it stands.