DVD's are going the way of the dinosaurs just as fast as CD's, if not quicker. There are better video disc formats available, and online downloads for software are growing exponentially. Not to mention that a lot of software to moving exclusively to the online space.

Laptops are meant to be portable platforms, if a user tends to use a lot of optical formats/or other external storage mediums with their computer they are inherently less mobile. It is fair to assume then that a desktop is a more suitable platform for that type of user.

As notebooks gain more battery life, internal storage, and computing power, the need for physical formats lessens, because the length of time that the computer will spend away from its 'home' will greaten, thus any disk or other physical storage medium that can't be carried with the computer becomes less available. And frankly if you are going to carry something stored on a disc with you, at this day and age there is no reason that it can't be kept on the computer your carrying.

Physical media won't dissapper, but its purpose/priority will continue to change