Couldn't it be argued that the Roman empire did become like the 'Satraps'? There ended up being two empires and then within that empire the military and civilian powers on the frontier provinces became more and more independent of Rome both in political power and how troops were levied (hiring more Germans) until eventually Rome could just be ignored. Isn't 476 just the year when the western consulate was sent to Constantinople thereby just a formal removal of a theoretical superior though actual power already rested in the germanic tribes that had been brought in as mercenaries.

Just trying to remember from my Roman history classes, not too sure if this is off or not though.