Just a note about laptop sales going up massively. People investing large amounts of money in desktop computers are usually, sure, making a generalization here, but gamers or animators or something of the like. They are people who want a **** good computer for a reason. The massive advantage of desktop computers over laptops is that they currently and probably will always out perform.
Laptops are widely used by business people and students for simple tasks like word processing, programming or web browsing. If you wanted to do something that was very power thirsty or resource demanding, you would choose a desktop. With the world becoming more networked and computer dependent, people who in the past operated businesses without computers now need one, hence the laptops, hence the sales.
Laptops are a convenience thing, desktops are for serious users, in general.