This just isn't true. If anyone was arguing that PhDs in general were worthless, then it would be a very reasonable point to think about. But in this case, it i

This just isn't true. If anyone was arguing that PhDs in general were worthless, then it would be a very reasonable point to think about. But in this case, it isn't really the PhD itself under discussion, it's the preparation and skills acquired through a course of a PhD. The difference is that the specific nature of a PhD program is pretty flexible. If professors see that their candidates aren't doing well in the job market, they can, and will, make adjustments to their programs.