People didn’t read back then like we do today.
The average person never, ever learned to read. The average person worked in a field, or in a workshop, produced what they needed to, and paid their taxes (which was whatever the tax collector told them to pay).
Reading was reserved for officials, Priests, and Royals.
So, what. Happens when that land gets conquered and those officials, priests, and royals are no longer in charge?
This is what happened in Egypt.