Windows XP To Get Longhorn Technologies

SilentChris writes "According to CNet, Microsoft is revising their plan for Longhorn. In addition to scaling back WinFS, they will also have separate releases of Avalon (the new graphical system) and Indigo (a new network architecture) for Windows XP and 2003. If most of the updates will be available for current versions of Windows, what is the incentive to upgrade?"