
This sounds like the patent clerk that decided to close the patent offie because he believed that all that can be invented have been invented and no new patent is necessary.
Not quite -- he's invoking perfectly logical market dynamics. The market has to be there for the 5D if Canon is going to throw R+D money into improving it. The 5D is a camera that is really hard for Canon to earn money from. It will never have volume sales like the rebels and 30D, and it will never have the premium pricing and 'pro quality' markup of the 1-series without being a flagship camera.
And there's no way a successor to the 5D will be sold for cheaper than the 5D's price -- it will either be a little tweak and sold for the same price, or it will be a big tweak and more expensive.
But whatever Canon does, people here will complain about it either way.