I would say that, illiteracy is a secondary topic while ignorance is center-stage. I say ignorance vs. illiteracy because the characters appear to not know better than to allow themselves to become manipulated, much like it happens in extremist groups where, if you break them individually, the members will prove to be weak, and in need of their own voice. So, ignorance to me is what led to everything else.
Absolutely! Mark Twain once said, "The person who doesn't read is no better than the one who can't". It seems to me that Bradbury is definitely honing in on the idea that so many just willingly allow the government and the firemen to destroy millions of books and with them ideas, imaginary places, knowledge, and pleasure without a fight. It is much like today when my students tell me they don't like reading. My answer is that it isn't that they don't like reading, they just haven't found a book yet that lights their fire. Once that happens, life begins! Without books, we are nothing. Keep reading!
I think it is certainly a topic to be commented on while reading the text. My students hate to read, and one of the main reasons I choose this novel is to show them the devastating effects of a society that has essentially become illiterate. It is not that they can not read, it is simply that they do not have the choice to do so. It is a form of mandatory social illiteracy.
Illiteracy doesn't seem to be a problem. Montag seems to have no difficult reading the books he surrepticiously picks up at the fires. There is no indication that a fireman is of a high social position that exclusively possesses the ability to read. His wife as well can read, and does so as she reads her script to participate in her TV shows. Thus literacy seems to be a general condition of the citizens of the time. One would think that such a repressive regime that so controls reading would develop an alternative form of communication, such as pictographs, voice overs, etc. (in point of fact, much as is becoming more prevalent in our own society, though this is justified by multilingualism, rather than illiteracy). This may be a flaw in the logic of the novel.
It is not illiteracy that is an issue, but rather what one may call "aliteracy," the non-reading of the common citizen. As Mark Twain said, "The man who does not read good books has no advantage over the man who cannot read them." The great books, requiring thought and judgment, are denied the citizens. It is the thinking, not the reading, that is a danger. Thus the government provides mindless entertainment requiring participation without thought. Through the outlaw of books the state is attempting to control thought. Through the medium of entertainment it has brainwashed them into not thinking, and not desiring to think.
The people in exile epitomize this level of thinking. Rather than taking upon the mission of preserving the skills of reading, they are preserving (without the reading skills) the books themselves. Thus the author is pointing out that the danger of books lies in the thoughts they generate, not the books themselves. And as Montag exemplifies, a government may control paper, but it cannot control individual thought.
Reading doesn't play an issue in the story as the boosk are unavailable to the citizenry. It's thinking that the government wants to control, not their reading. Illiterate people have no advantage over people who can read exceptionally well in this society.