The author doesn't specifically state it but the problem, at least in my case, is one's definition of work; I don't think I'm alone when I used to think my code spoke for itself and that's that. There are a few problems with that but essentially the issue is many of us myopically ignore other seemingly unimportant work-related tasks such as building relationships, personal marketing (I know that sounds like a buzzword phrase but it's true), among other examples.
Basically, at its core I believe that hard work does lead to success but our definition of work gets in the way.