Peons work at Google because it's Google, but the people this article is talking about (and the people Marissa Mayer needs at the moment) will go where the opportunity is.
I know a lot of APMs. Most of them are actually still at Google, but the ones that leave usually do so to found or be the first PM at a startup.
Also, from a self-actualization perspective it may be preferable to by VP of Worldwide Widgets at Yahoo than Director of EMEA Widgets at Google.