Nonsense. There was Scripture to rad and there were business records to read.
List of libraries in the ancient world
https://en.wikipedia.org/wiki/List_of_libraries_in_the_ancient_world
The OT Scripture is full of recorded instances of decrees being sent out to people in many of the nations mentioned besides Israel. In ancient Israel if a man divorced a woman, he was to give her a WRITTEN divorce certificate. An odd command if most of the people could not read or write.
Since you have yet to provide any evidence to support your contention, we can pretty safely conclude that it’s wrong.
Several years ago I watched a documentary on that. Frankly, I was amazed at just how any people back then could read. I had just never thought about it. Like you said, decrees were sent out all the time so someone had to be able to read those. There were important libraries in old cities. What good were they if no one could read?
And it’s not the first time, either. Must be that contrariness blocking their sight.
Oh, please, these weren't lending libraries as we know them...they were in major cities and were used by legal people, governmental folks, maybe some rich folks, but the average man on the street knew NOTHING about them....The written divorce certificate was written by a scribe...don't you ever read a history book....the reason that you cannot read Swahili is because you don't need to and because there isn't a book, written in Swahili within hundreds of miles....and you don't have a car, you have to WALK to get there....good grief.