Whatever became of the Roman Army in the West

[Robert Vermaat]

in short, the Romans outsourced their military to Germans due to financial and manpower shortages and by allowing Germans to serve under their own ethnic leaders rather than Romans they outsourced, by fits and starts, the political structure that gave the empire its relevance.

Well put, but not 100% accurate. The system you just described already originated earlier, and was in use even in times of Roman strength. Of course, when Romans became weak (civil wars, economy), this system became dangerous, especially because of the second characteristic.
What you don't describe is that the Germans originally did not replace Roman military, but added strength to already available numbers. The Roman armies grew in numbers during the 4th c., and total troop strength along the borders (regular forces, no hired federates or mercenaries mind you!) also reached a high level. Of course, when economics dictated that this number fell, it became easier to use Germans on short-term contracts.

That said Procopius states that in Gaul their was a Roman army serving under their own standards in the mid 6th century after the end of the Western Empire. Presumably they would have served the Frankish kings as they served the emperor and any distinctions would have evaporated in the gradual transition from Gaul to Francia. From recall Gregory of Tours doesn't mention any such soldiers in his account so they must have disappeared by the time he wrote his history in the late 6th century

We don't know whether Procopius exaggerated or not - he managed to describe two Britains as if they were two islands. He seems to have had only scant information about what happened in the former Western provinces. I like the story but it might be a folktale.

Having said that, we know that the former Roman population continued to be ruled under their own Roman laws, whereas the Germans were subject to their own laws. Of course this vanished gradually over the course of time, but for a long time, the populations were distinct. In Italy, the Goths only claimed sovereignty over the Goths, and always asked Constantinople for their consent (I think this only changed after Belisarius campaigned in Italy). I think this also shows why Roman military had no problems fighting for Germanic kings, because that's mostly our modern perception: to them a general was a general, his jurisdiction could be fluid and the ethnicity of an army had never been a problem. The shift from a 'Roman' army under a 'Roman' general with Roman and German troops to a similarly-looking 'Barbarian' army under a German general with German and Roman troops is only very small.