My assault on your thesis was by means of showing that major elements of Greek culture (shall we add Plato, Aristotle and the Presocratics, etc. by the likes of Boethius) were translated into Latin. The dying back you are describing comes later, during the Middle Ages, when learning of most every sort dies in the west, so I am not certain why you chose to articulate a thesis which suggests that Greek ideas died in particular, when truly, Greco-Roman ideas (along with those of many other cultures) died. There was a fear of knowledge during that time, and it took rather odd sets such as the Scotti Peregrini and others of their kind to keep the ideas alive until the Renaissance.
Trying to update my sig ...