Why do Greek/Roman scholars have no manuscripts earlier than 11th - 16th century ? Are there earlier ones?

Question

If you look at the baseline Greek/Roman texts for the Loeb Classical Library (and other similar translation series like Oxford/Cambridge) for authors from the 4th Century BC through to 1st Century AD, there seem to be no early manuscripts in existence. The ones we have available all seem to be from the middle ages rather than the dark ages. What is the typical history behind what we have available, and why do there seem to be almost no manuscripts prior to the 10th Century?

Answer 1

The Western Roman Empire was overrun by the Goths, Huns, and Vandals, who were mostly illiterate barbarians. They had no use for the written word, so they burned libraries and monasteries, along with anything else they could not loot, or did not understand.
The Eastern Roman Empire lasted much longer, and was conquered by the Turks who had a thriving culture of their own, and more respect for knowledge and learning. They preserved the written legacy of Greece and Rome.
Western Europe began to "rediscover" the Greek and Roman works when the monks and scholars accompanying the Crusaders brought back what they found in the Middle East. This would have begun during the 11th century.

Answer 2

Dark Ages is the easiest and fastest explanation. Longer ones involve explanations of various "sackings' or conquerings of Rome (Rome had already appropriated greek gods, culture, literature, etc.) The beginning of the end (fall of rome) begins in early 4th century with the death of Constantine the great, followed for the next 100 years plus of invasions of the Visigoths, Huns, etc. I don't need to explain to you what happens to literature, libraries or culture in times of war- look at CNN. We're lucky to have anything from those years that survived. And they must have, though only the later manuscripts exist now, because we know when Aeschylus, Aristophanes, Plautus, Terence, Menander, etc were writing.