On the contrary, one of the documents in this collection includes a man protesting that he could read something for himself, which implies that literacy wasn’t widespread.I believe this is Lachish Letter 3 (on which more here), not on of the Arad ostraca. But aside from that, this is a very good discussion of the issues. Note especially the following paragraph:
The study itself states that the kind of literacy levels that the Arad documents demonstrate only occurs again in c. 200 BC. The implication seems to be that it’s unlikely the biblical documents were written in the intervening period (600–200 BC) when literacy levels were lower. But there are so many problems with this inference. First, the claim relates only to the region of Judah. It says nothing about literacy levels outside of Judah. Second, the claim uses blank evidence (little apparent writing in 600–200 BC) as a warrant for reaching a positive inference (it’s unlikely the biblical documents could have been written in this period). But logically this is unwarranted. To state it another way, a lack of evidence is not necessarily evidence of lack. It could be that we just haven’t found all the other document caches like the one from Arad that date to this period. We just don’t know! Third, you don’t need most of the elite, let alone most of the population, to be reading and writing to create conditions conducive to the writing of texts like the ones in the Bible. You just need one competent literate person who can ‘put pen to paper’. And that person could write for themselves, or even for a whole group of people. One person can pen the imagination of hundreds! And fourth, since there evidently were biblical texts that were written in Judah between 600 and 200 BC (e.g. Haggai, Zechariah, Malachi, Ezra, Nehemiah), the very low literacy levels actually count for nothing.Cross-file under Epigraphy. Background to the story is here and links.