Cynics claim that Microsoft is trumpeting Windows 7 to divert attention from the Vista trainwreck. Some of that may indeed be true, though it does seem to me it is a bit of a stretch to divine someone's motive from afar and based on so little evidence.
This post on Ars Technica is more likely to contain the reason for all Microsoft's talk about the future. It seems they are trying to get us used to the idea of renting software as we need it or need to update it (which they can control by killing off any component that isn't generating the required revenue any more).
It's going to be fun to watch this play out against FOSS alternatives or more traditionally marketed products, such as those from Apple.