In italy you have a saying along the lines of: "Doctors usually suffer from what they cure"... meaning they're too busy being good and helping others do that one thing that they don't do it for themselves.
I see the same for myself: I have 50+ apps in the App Store but unfortunately none of them are at levels I help my clients reach. Greatness requires time & effort, which we have a limited amount of.
In short, just because they haven't implemented what they preach doesn't mean they're frauds. However, always remember to make your own choices.