This is inspired by some of the periodic discussions we have about the Western Roman Empire holding onto North Africa, or retaking it in the 440s or 460s from the Vandals. Okay, yay, they take it.
But the Western Empire had periods of seeming resurgence time and again. Aetius, for instance, could plausibly have claimed to have revived the empire and restored some stability. But then something went wrong, and the barbarians carved off another piece of the empire. This suggests to me that the Roman state was weak, and that it had a hard time recovering from blows. Retaking North Africa from the Vandals just means the Visigoths seize it a generation later.