I don't know that much about it really, but I'd guess that some of it also goes back to the fact that Jung was never as popular in the psychology departments in academia as Freud and the behaviourists. The spiritual aspects of Jung might have complicated things, and some other ideas about the human mind were probably not always politically correct either. I certainly understand the need for (and in Jungs case, the relative lack of) scientific evidence supporting the theories, but I still think that Jung has been given less attention than he deserves.

From what I can see from the table of contents of the Oxford Handbook is that seems to have a emphasis on clinical psychology, and the Jungian models (MBTI, Keirsey, and so on) are not (should I say primarily?) clinical models of assessment.