Isn't there a fundamental difference between the FB rule of restricting the top rating to just 2% of employees and the Microsoft rule of decreeing that there mu

Isn't there a fundamental difference between the FB rule of restricting the top rating to just 2% of employees and the Microsoft rule of decreeing that there must be a bottom 10% of "poor quality , less talented, undesirable elements" in the workforce. The FB system doesn't make the non 2% feel rejected and unhappy - it just makes it very hard to be crowned the superstar which I think most people find perfectly acceptable. To address the relatively longer period of MS employee retention, Microsoft employees (esp the technical ones) in general work on a set of technologies (C#, NT Kernel, SharePoint,...) for which MS is the place to be. They build up expertise and then if they have to leave to join a comparable company, they need to rebuild in a different set of technologies most likely open source stuff of which there is very little in Microsoft. Now if you are a Linux kernel hacker / Python guru/... at Google/Amazon the world is your oyster - everything you are good at transfers readily to companies/roles of similar stature outside. Its almost like Microsoft technologies are a moat around its castle that keeps talent from leaving. full disclosure I worked at Microsoft for about 7 years before leaving.