My theories is that the manufacturers listened TOO MUCH into their own constituents/clients in where Canon came out with the 21MP and everyone, even canon folks, especially at first were vocal "we dont really NEED 21MP but we will learn to live with it"... and then Nikon folks, while they loved the IQ of the D700, were slightly embarrassed to ONLY have 12 MP... Nikon decided, well screw you, we will come out with a camera that will make everyone take notice, while canon, already with the 21MP camera, realized most their clients, who are 5d users are happy with the 21MP size, decided to not push the envelope so much and focus on other avenues to improve their product... For those who say "Canon/Nikon NEVER listens to their customers", the Canon 5d3 and Nikon D800 will now prove that theory wrong.