Maybe someday but for now Mac sales are going up -- not down. I can't imagine they'd walk away from that market. I could see the two platforms merging in certain ways. For instance if you added a multi-touch screen to the current MacBook, retaining the keyboard/touchpad, you'd have an interesting platform. You'd have desktop multi-touch apps very similar to iPad apps but you'd also be able to use traditional OSX apps. There could be some system wide multi-touch features along the lines of what they're doing with the multi-touch trackpads already to enhance these applications.