Google's ambition is to have a searchbox in front of someone all the time. From that small rectangle of user interface, maybe it measures 1 square inch, Google has built a massive business.
Microsoft owns far more user interface real estate than Google--you'd think it would be ahead of the game.
Microsoft's business model is very profitable and it is based on selling software rather than monetizing a square inch of space in front of someone. It's interesting that MSFT hasn't been able to capitalize on its far larger user interface real estate in the same way Google has, at least so far.
Is this a cultural block? Whatever the reason, it's interesting. Microsoft's position reminds me of my favorite American saying: "You can't get there from here."