They know there is money to be made as well. In fact, if they were smart, they'd just charge like five bucks per license for Windows and do that every three years with a new version. Considering there are roughly 1.4 billion Windows users in the world and just for the sake of argument let's say that the .4 billion won't upgrade each "cycle", that still leaves 5 billion to be made every three years, JUST from Windows licensing. Along with the 10-16 billion it's Xbox division has been raking in each year, not a bad haul if they were a little smarter about it. At 100 bucks a license, you end up with a LOT of people who absolutely won't upgrade until and unless they absolutely have to. At five bucks a license, pretty much everybody would upgrade every three years if their hardware supported it.