I would also add that an inductive argument for the Xiongnu (or their descendants) as leaders of the Hunnic confederation is that in lockstep with the Hunnic invasions of the Central and Western Europe, a sort of power vacuum appears in the areas of the formerly dominant Xiongnu Empire, from which new confederations and peoples arise over the following centuries -- namely, the Uyghur, Khitans, Rourans, etc and eventually the Mongols and Jurchens.