One theory asserts that the significance of Kageyushi gradually waned in the middle to late Heian period because official posts increasingly became 'family business,' in other words, a certain post was exclusively inherited by a member of specific family.
平安中期～後期頃から、ある官職を特定の家系が相伝する「官司の家職化」が進行していき、勘解由使の存在意義は次第に薄れていったとする見解がある。