You are absolutly out of your mind if you think Windows is even on the road that heads the way out, so to speak.
Start with reality. MS does not simply work on a few basic pieces of software, like their flagship OS and Office suite, along with cooking up patches for XP. MS is always going to have people who are looking at what might be the next big thing and looking into how they might become part of it.
Agreed, sometimes MS is a day late and a dollar short when getting into the game, and it cost them, like the Zune, a great device that is stuck wishing it could catch up. But by the same token MS has had some considerable successes such as the X-Box and some have yet to be shown if there will be any long term success like search. But the real issue is, when it comes to MS letting someone get such a jump on them in any area that counts, as far as their long term viability goes; FORGET IT.
Anyone with a brain can see what the reaction is at MS when they even see so much as a meager blip on the radar that might pose a genuine threat to their position. Witness the wildly quick turnover from Vista to Windows 7.
Anyone who uses Vista regularly, who doesn't have an existing preference for a non Windows OS will tell you that in the end, there is nothing really wrong with Vista, it works fine and is secure and does exactly what its supposed to do. But! Even though the other two OS's (which we all know and hence need not be named)only wish they had the market share Vista has, MS has detected that Vista has not quite meet their expectations in sales (blame that on XP's still venerable workability more then anything)and as such they have seen that tiny threatening blip on the radar and have reacted, with what some would call lightning speed compared to Vistas long awaited release, and hammed out Windows 7 to an overwhelming round of applause.
Just because MS is actually a business, and makes decisions based on what they expect will be profitable, don't think that means they cannot save themselves from some obvious impending catastrophe. In Microsoft's relatively short history we have clearly seen at least two common approaches to exploiting the marketplace.
First, they look at whats new, whats coming up and see if there is a reasonable way to get into that new market, but don't blow the bank in a rush to create some perfect product for that new market because even some new perfect products fail to win the day sometimes, and if the bank was blown to create it and it doesn't sell enough, then its down the tubes for the whole works. Unfortunately that leads to some hit and miss like the X-Box and Zune.
Secondly, keep an ever watchful eye on the very bread and butter that created the company and drove it to the market place; the core software sales such as Windows and Office. Keep all eyes pealed for that tiny blip on the radar, and if that so much as raises its head, pull out all stops and correct the course at all costs and recapture the moment so to speak. Never ever let that blip go unanswered. That has been shown again and again with MS. Recall the Windows ME to XP transition? MS will watch for every and any threat towards their bread and butter in the marketplace and you can count 100% that each and every blip on that radar screen is scrutinized with far more care, attention and rapid heavy handed response then their silly farting around with mp3 players and video game consoles.
Saying that MS is just going to sit around and watch Google/Android slowly but surely take over the OS market over a period of years without being able to notice or do anything about it is like saying a hunter is going to sit in his log cabin and listen while an 800 pound grizzly bear makes it quite apparent he is gradually chewing through the front door, and the hunter never bothers to load up his nitro express elephant gun and blow its head off although he has plenty of ammunition and thats what he has always done in the past.
Its possible in some wild or unusual circumstance but so unlikely its silly to speculate its what will happen without being able to explain the reasons why. And currently, there is no reason why.