Further, using only monetary reward as a metric for PhD utility is not reflective of the reasons why people pursue a PhD.
Even excluding monetary reward and the fact that a PhD is often required to do original research in industry (and receive a position as a professor at a university), the people pursuing a PhD are doing so because they are obsessed with the area they are studying and want to have sufficient knowledge to expand the available information known about the field.
The article is overly dismissive of knowledge being considered as its own reward among the demographic and eschews the trait to focus only on monetary reward, and as a result the conclusion is nonsensical by concluding that the smartest individuals in their areas of interest are habitually irrational actors.
An individual has to reach the giants to be able to stand on their toes so to speak and getting a PhD is often a requirement for even being given a chance to do so.
A more damning reason to not pursue a PhD is that the hours are insane and academia is increasingly less available as a career path, which for a lot of fields is the only option for employment that will utilize the specialized knowledge for a PhD holding individual.