So they productively employ some fraction of those people (I'd guess, conservatively, less than half), and they pseudo-productively distract the rest with poorly managed fool's errands. And don't think it's a case of "you don't know until you try" - in most cases, everybody knows. General Managers will seize on any misguided idea with enough plausible deniability in order to build their fiefdoms.
It's like a bizarre kind of welfare system for the upper middle class. A few people do amazing work and ship great products. For the majority, the most significant thing they accomplished was passing the hiring gauntlet. But they all get to live in big houses and drive BMWs.
An institution can work on the whole, but still be grossly inefficient.
2. "welfare for the upper middle class" is a perfect description of middle-management.
They seem to show some improvement lately, but Microsoft still looks very much like middle-management realms, a tentacular corporation with little movement and even less focus.
Quite simply Google could never could never replicate Microsoft's culture because there never was a time when when a large enough fraction of employees had fuck you money. Microsoft's culture is different by virtue of the fact that venture capital has never had much of a say.
Hence a positive vision of "a computer on every desk" rather than a mere admonition to not "be evil".
Google's stated mission is "organize all the world's information", considerably bolder than "a computer on every desk".