Can you back up this claim of an illiterate Plato? That sounds like the sort of assertion this post complains about. Plato's dialogs do have Socrates complaining about book-learning.

AFAICT literacy rates in classical Athens are uncertain. I recently read http://www.amazon.com/Intimate-Lives-Ancient-Greeks-Peoples/... which left me with an impression of relatively high rates for male citizens, but I don't remember anything concrete. Searching turns up http://www.cambridge.org/us/academic/subjects/classical-stud... which says the orthodoxy is for low rates, but argues against it.