Whats the ROI vs a Masters for people going directly to Industry? Did they even intend to do that or realized the Academic Door was closed for them and had no other choice?
The fields where you are bound to academia for a reasonable ROI are definitely the humanities, since there is essentially no demand for a history PhD in the private sector, or an English PhD. It can help for job hunting in an unrelated field, I guess. But, a chemistry PhD? or any other applied lab PhD, it's not like you're shooting yourself in the foot by getting an advanced degree in such a field.