Funnily enough, the racial lore for Midlander hyur have long stated even back before 1.0 was launched that they are "trained in letters from a very early age", meaning that most Midlanders at least are literate, if not highly educated. There was a thread a while ago that debated just how educated Eorzeans were which had some surprising ideas.

I guess though that we now know exactly why the books you can buy as furnishings for your house/private chambers have blank pages.