"Microsoft has dismissed claims that Linux is more cost-effective for businesses, arguing that Windows is cheaper over its total lifecycle."
Even this is a stretch, but he may be right. Windows is cheaper over it's lifecycle. BUT, the key thing there is Windows has a lifecycle. Which means it will eventually be replaced, costing more money. I don't think that linux has a "total lifecycle" such as that, since it isn't required to be replaced every X years. So you might be spending X for Windows 2000, then when you're forced to upgrade to XP you're paying X^1.5, longhorn ends up costing X^2, then whatever after that just adds up.