I didn't go to grad school so I could use the degree; I went to grad school so I could get the degree. It wasn't an attempt to lay the foundations of a career, although that was certainly a possibility; it was because it was a challenge and the topics were interesting and I had nothing else pressing to do. I refuse to be trapped by my education. If I decide I want to write children's books, become a police officer, join the peace corps, learn carpentry, start my own dojo, teach kindergarten, work for a non-profit, or run for political office, it is not a "waste" of or disservice to my education. Doing something just because it makes use of my PhD would be a waste of or disservice to my life. I can only assume that anyone who says otherwise stayed on a lifelong path set by a decision made in college and thinks everyone should suffer the same fate.