Key word being Yet. In 1984, when the first Mac was released, people said the same thing back then - The Mac would never replace the Apple II / Lisa or command line. As we know the rest is history.
If you read my original statement, there is no "yet" in it. Apple may decide to replace desktop/laptop computers, but I can assure you that I will not buy an Apple "computer" that isn't solely in tablet form. I will reluctantly go back to Windows for my personal home computer. It's that simple.
If you are referring to the fact that all manufacturers will only be making tablets, then I will have no choice. But, as long as there's a choice, it's a no brainer, and this is the key point - in my opinion.