I severely doubt this is gonna happen. Here's why.
The Windows OS is the foundation for everything else MS sells. Stop selling it, you eventually have to stop selling Office, Games, IIS, etc.
How much time and money would they have to spend to port all their apps to other OSes? They would have to do this or the above would happen.
Doing this would not only end the case, it would prove the DOJ's case, IMHO.
MS looks bad enough in the public's eye now. They would never recover from doing something so stupid.
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That said, I also don' think this would have the immediate impact everyone seems to think it would. The world isn't going to come to a halt is Windows stops shipping. First of all, there is an incredible number of copies alread in the channel. Second, what is the real lifetime of a Windows rev? My upgrade cycle has been about every three years and could be extended to five if I wanted. I'm pretty sure that the world could run on the current revs of 2k and XP for more than long enough for a viable replacement to be found.
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On another note, we all poke fun at Mac and Linux zealots, but I have found a group of people worse than both (probably because they are made up of the most vocal of both): anti-MS zealots. Oh and worst of all are pro-MS zealots.