Microsoft doesn't play the same sort of long game that google does. Microsoft plays a traditional long game: market penetration, brand loyalty, development stack, "synergy" (real or imagined), etc. Google plays a much more subtle game. They'll do something like GOOG411 just to get better voice recognition algorithms. They'll also do things like develop a state of the art web browser just to jostle the browser development community out of its laziness and propel web standards and browser performance forward. That sort of thing is just not in Microsoft's DNA to do or even conceive of doing.