I'm the author. It's a fair point - I wasn't sure how concrete I wanted to get about my specific experiences. Or maybe I was concerned about people being able to trace my actual job history. Then again - it's all on LinkedIn anyhow so I guess those were invalid fears.
There is definitely a happy medium and early career job hopping might be more productive than later career job hopping.
As an employee the only thing you have to invest is time and really not as much of it as you would think IMO. Invest it wisely.