You know how monkey-traps work? You make a small hole in a coconut shell, put some bait in it and tie it to something. The monkey comes along, reaches in for the bait and grabs a handful. But when it tries to retrieve its prize, it can’t: its fist won’t fit through the hole. The monkey is trapped by its own greed. Under pressure, the animal isn’t able to choose between escape and letting go of the goodies; you just walk up and whack it over the head.
That’s the situation Microsoft is in right now with its virtualisation strategy.