You ignore the article's point about the risk of choosing a proffession. For example, what's the return on investment for the worker that trained to be a professional car welder in Detroit? I don't know if "-100%" captures the loss.
In your example, it sounds like we take the job and location as a constant. If they guy can't choose a profession that has good chances of surviving throughout the years, he'd be really bad as an investor.
However, there is a point to be made about how the loss of livelihood, or a reduced standard of living can be devastating. It's just not the same economically.