Mary Midgley has some provocative thoughts on (not) having a doctorate.
As someone who has one, I cannot say it necessarily makes me more capable of seeing the big picture, or the details. I guess it depends on your subject area and the approach you take to your thesis. Do I think that PhDs can be inadequate or irrelevant to a person's teaching ability in HE or to producing fine research? Yep, because they are mostly dominant because the boundaries needed to shift rather than because of their intrinsic value or purpose (in much the same way as now it is almost impossible to get a teaching post in HE without a PhD, PLUS a list of publications).
What I would say is that a PhD can be useful: but that shouldn't make anyone believe that just because they have one, they are better than someone who doesn't.