crewmeal
Microsoft would go bankrupt if they didn't strongly nudge the customer to buy newer, newer.
A dilemma of theirs is Office software. People buy a copy and use it for a long time ... during which MS get no additional money. This could explain Office365 ... which will produce a continual flow of income from its users.
It sounds as though Google may be working on ChromeOS to be pushed as a replacement for WinXP. We shall see. Interesting times.