It takes a little more effort than just to slap a touch screen on a laptop. The OS must be able to adapt to touch input. Just ask Microsoft if that is an easy task. It took them more than 10 years to get Windows to behave like that. Of course Apple could just install their IPad/iPhone OS but then it would no longer be a "MacBook Pro" but more of a "MacBook Toy"
Macs already have the worst aspect of Windows touchscreens: reflectivity of their glossy glass screen (though Lenovo does their X1/X1 Yoga touchscreens right with anti-glare coating).<p>For us keyboard aficionados, I can only hope they introduce non-glare screens alongside touchscreens so those who care about ergonomics get something out of the move ;)