[jschwartzi]

Yeah, I mean it's not as if people haven't learned new things from their conquerors throughout the ages. For a modern example look at Japanese society now versus Japanese society pre-WWII. The US completely remodeled their society. While we have long since handed over control of their government to the Japanese people they continue to have strong Western influences in their buildings, fashion, and culture. It has a distinctly "Japanese" tint to it but if you visit Japan you'll observe largely the same social mores around commerce as exist in the US.

Within that context it's hard to believe that the European tribes simply forgot how to build roads or monuments or architecture after Rome ceased to influence them.