Foundation and Empire
I just think they're following Asimov's lead:
A formerly all-powerful empire that is no longer able to maintain, let alone develop, it's advanced weapons technology - but which remains a threat due to the strength of its remaining "old" weapons - versus a bunch up upstarts that haven't got the resources to build their own mega-weapons but do get hold of a few from the Empire by economically defeating small parts of it at a time.
Biting the hand that feeds IT
