Article in Science Magazine tackles the question of whether a PhD program overqualifies or underqualifies someone. My opinion is that with training nearly exclusively in research in one single research area that PhDs have a valuable, but limited skill set. Furthermore, many people are impressed with those who have PhDs, not least those that have a PhD. A PhD degree is primarily only relevant in the business sector of colleges and universities.
http://sciencecareers.sciencemag.org/career_magazine/previous_issues/articles/2014_10_14/caredit.a1400253
