Of course, there are those amongst the Ashikaga and Tokugawa shogun families and so on that took to using the Minamoto clan as part of their name and, their relatives' monopolized aspects of government service on a hereditary basis.
もちろん、足利将軍家や徳川将軍家など源姓を称する一族に世襲の官職として独占されていた側面はある。