Sigh...is this the terycarl version of Bible history? Are you aware that great libraries existed in Egypt (Alexandria), Rome, Anatolia (Constantinople), Africa, Greece, India, Iran, Iraq, Israel, Syria, China as well as others (http://en.wikipedia.org/wiki/List_of_libraries_in_the_ancient_world)? What do you think they contained, picture books? If nobody could read, why did they exist? Who wrote all the thousands of documents they contained? Are you aware that the Bible was the book most early Americans used to learn to read? That young Hebrew children used the Scriptures to also learn to read?
I'm not sure who you mean when you say the "vast majority of people" couldn't read. It certainly is provably false as we STILL have books that date to before Christianity existed. If you want to toss out numbers (i.e., Roman Catholicism is 2014 years old; the printing press didn't exist for 1600 years) to demonstrate the antiquity of Roman Catholicism or there wasn't a need for the Bible, it's your responsibility to be accurate - they are hardly meaningless numbers.
of course I am aware of them, but they certainly weren't like your local public library where virtually anyone can check out a book and take it home. The average person could not make use of those libraries because they couldn't read. Books were not available to the average person because they were hand written and extraordinarily expensive. The major libraries, of course had books, documents and such, but if you lived in say Bethlehem, you had to either walk or ride a donkey to wherever the library was....then you might be able to actually hold a book and perhaps, if you were one of the very few literate people from there, obtain some knowledge from it.