Answer:
Lack of technology
Step-by-step explanation:
Africans most specifically the Ethiopians and Egyptians were known to have written some of their ancient history in hieroglyphs. However, this is different from the modern written system which requires ink and paper.
To be able to write history down, over the years requires to have ink and paper, which the African communities lack the technology to produce in the past. A similar situation is the period of the Prophet Muhammad, where there was a lack of technology to produce ink and paper to write the Quranic revelation. Prophet Muhammad and his disciples initially had to memorize the revelation to preserve it.