Microsoft is not just going to idly allow WINE to steal its userbase, even if WINE becomes 100% perfect and everything runs and works exactly as it would on Windows. MS has a lot of money and they will use all of it to keep Windows alive, whether that means pounding everyone involved in open-source with streams of litigation, buying off distributors (see EeePC), propaganda and FUD campaigns and whatever else.
MS already sees Linux as a threat, which is what the deal with Novell is about -- it was a proclamation to all Linux users that Microsoft isn't just going to let you stop giving them money. You either go through their approved vendor (through whom MS makes money) or you risk big SCO-esque (targeting users, not makers) lawsuits for patent infringement, etc.
To sum up, WINE is good and nice, but as soon as Microsoft perceives it as a real threat they are going to mobilize billions of dollars to put it down.
MS doesn't care about virtualization because you still have to buy Windows to use it.
MS already sees Linux as a threat, which is what the deal with Novell is about -- it was a proclamation to all Linux users that Microsoft isn't just going to let you stop giving them money. You either go through their approved vendor (through whom MS makes money) or you risk big SCO-esque (targeting users, not makers) lawsuits for patent infringement, etc.
To sum up, WINE is good and nice, but as soon as Microsoft perceives it as a real threat they are going to mobilize billions of dollars to put it down.
MS doesn't care about virtualization because you still have to buy Windows to use it.