One may ask themselves why Microsoft has resorted to using tactics such as how much a PC costs vs a Mac. Look at their new commercials, like the woman going to find a PC under $1000. Well, if you haven't seen it, I'll let you in on it. She's told by an announcer that if she can find a PC for under $1000, she could keep it for free. Well, she goes into the 'Mac' store (yes, she calls it the Mac store, not Apple) and leaves immediately, stating that the only Mac she was able to find for under the limit was one with a 13" screen. In order to meet her requirements for herself, it was to be a 17" screen, a comfortable keyboard, and of course, under $1000. So she makes her way to a best-buy clone, and looks around. To her amazement, all the computer there had better specs, and she eventually settles on a $700 HP. Yes, not the point, she had to pay for it. Way to keep your promise Microsoft. Anyhow, that's besides the point.
Many people say that in order for Microsoft to combat the current problems they're having, they need to do a complete redo of their OS. This is a terrible idea, from a Microsoft perspective. Vista was as far as they can go at one time without losing a terrible amount of share. The amount of people complaining that their software doesn't work, games, applications, was incredible. Now, if they were to scrap everything that they have, and start from scratch, they'd be unable to achieve the market share they once had. Sure, some die-hards will continue to use Windows, and companies would likely continue to make software based on the new OS, but so many people would likely turn to either Mac or Linux. This is because they are already stuck having to try and learn the new OS, so they will try something new.
So, in reality, if Microsoft wants to keep their position at the top for as long as possible, they're going to have to continue with their current business model. If they don't, they don't stand a chance in this economy, let alone against the spectacular software available. So, don't expect a drastic change, expect Microsoft to stay Microsoft until the day they become the next BeOS.