I think the 10x productivity thing might be true in unrestricted settings, where everyone is their own boss, but I doubt it holds up in heavy corporate environments. The reason is because you often have to justify your actions to other engineers, wait for feedback, etc. And commit procedures can be long and painstaking. So while some are certainly more productive than others, I doubt it's 10x.
It really can be. The least productive people are not only producing less work in more time, they are also producing work that needs to be reviewed more thoroughly, needs to be redone, or causes bugs whose fixes take more time than the original implementation took. Add all these up and you can easily exceed 10x productivity compared to a developer who gets it right the first time, producing code that's clean, easy to maintain, and easy to adapt to changing requirements. Not only have I seen it first hand, I've seen it over and over, and I expect to continue to see it throughout my career.
