Not really, they still support backward compatibility to a much greater extent than any of their competitors. Check out the history of the 2 biggest competitors they have in desktop OS anyway, Apple and Red Hat, both of which have completely abandoned entire platforms before, and also have a history of announcing such changes unexpectedly. You’ve still not named any legitimate threat that can better answer your problem than MS.
Irrelevant. You're missing the point entirely. It's not about the current market.
It's about an unfilled need. Businesses *need* to run their existing proprietary software. Since existing products like Vista and Mac and Linux won't let lots of XP/2000/NT/98 business software run on new machines...that means that there is an unmet market demand for an OS that runs old software on new hardware.
And any student of capitalism will tell you that an unmet need, especially when well financed, will eventually be filled by the Market.
Which is to say, MicroSoft is making a grand strategic blunder by rolling out and sticking with an OS that isn't backwards compatible with a Trillion Dollars worth of legacy business software.
And please, stop repeating that no one fills that need any better. Slap yourself and catch on to the fact that there is a large unmet need out there.