Microsoft has tried very hard, over the years to reduce piracy of Windows and its other software in various Third World Countries like China and India. For the most part it has been successfully increase the percentage of people who buy its software.
However, with its stubborn refusal to listen to its customers, Microsoft is risking fueling the engine of piracy. As people want Windows XP and its not available on shelves they will turn to other vendors, who have no qualms selling fake copies after the deadline. There are so many reasons for Microsoft to not stop selling Windows XP that it seems literally insane if they go through with it.