Microsoft on the other hand writes an OS for any PC and any user. Any hardware combination and an almost infinite set of software installed and perhaps running

Microsoft on the other hand writes an OS for any PC and any user. Any hardware combination and an almost infinite set of software installed and perhaps running simultaneously. Strictly speaking, that's not true. Microsoft doesn't generally write an OS that is compatible with hardware; hardware manufacturers make hardware that is compatible with Microsoft. Microsoft may do what it can to make their job easier, but so does X.org. So, while it may be true that this is a blocker for Linux in the consumer pc market, and it may be true that Linux won't ever become a major player in the desktop market, It's not the X.org or Linux developers' fault that that is the case; it's the market's, and statements like "X.org has a lot to learn fro Vista and Windows 7," are really unfair.