I've not yet RTFA, but your statement seems like a sweeping generalisation and overlooks other possibilities. In various industries, a doctorate is a pre-requisite for most roles (e.g. semiconductor engineering). You might just squeeze in with a Masters degree, but more often a Ph.D. is required to even get your foot in the door.
Given the erosion of standards for 'regular' degrees (B.Sc., B.Eng., etc.), the demand for a higher degree is easier to understand. You'll get more applicants as a result.
What I find interesting is the ability to study a highly technical field, get a Ph.D. and then find next to no employers in that field within the country. That's what I ran into in the UK - by the time I was out of the Ph.D. grind, the relevant employers had all left for greener shores. I had to follow them. As a result, the UK has benefited very little from the expenditure on my education.
Even before undertaking my Ph.D., it was very clear that working in academia was not going to be my thing. The lack of resources and funds stood in stark contrast to the facilities available for similar R&D within companies. Having to fight for funding every n years was far from appealing.
This is from a UK-perspective, but I hear similar concerns from those in the US.