Reading the article title I immediately thought of those leaving Google for Facebook. This IS happening. They're doing it to catch the FB IPO. OP mentions this

Reading the article title I immediately thought of those leaving Google for Facebook. This IS happening. They're doing it to catch the FB IPO. OP mentions this topic but mostly talks about his view, which I get. On the other hand, I've spoken with plenty of ex-Google employees who've left because Google is getting so large and has so many 20% projects that it no longer feels so entrepreneurial being at Google and so they leave. These are employees that don't care about a business model and just want to see their projects see the light of day. So, Google has a problem retaining great engineers? Sure, it doesn't apply to OP, but that doesn't mean it's bullcrap.