Unless a billion buys immortality, Bill G is still mortal so whether he's six feet under or off curing the world doesn't change the fact that Microsoft, for the moment, is completely rudderless. If there is only one man to lead a company that means it is dead meat because tomorrow is not a guarantee and the investors know this. This is why Apple is working to codify what makes Apple, Apple.
Agreed, entropy is inevitable, and a transition is required. However leaving Steve 'crazy' Ballmer in charge while you 'walk the earth' is a less than stella plan.