On the point of pentameter and other ancient writing quirks. It’s because writing was expensive and not really that common. Ink, paper, quill. It all had to be painstakingly made by hand. Then all the training on reading and writing was a huge time investment as well. So it was relegated to the high classes. And slaves, they used slaves as scribes and basically as personal computers.

So, most of culturally relevant works were actually poems. Lacking writing tools, long passages of texts are hard to memorize. But, poems in regular rhyme and accompanied by structured melodies are actually very easy to memorize. The Odyssey was one such a song.

A master could teach his disciples the words and melody of extraordinarily long passages of information. Names, history, dates, myths, moral essays, by teaching the song. Performing the different passages several times allowed memorization and then they could perform this either for entertainment or for study and analysis via rethorical discussion. This oral tradition is how we have theater plays, stories and songs from 5 thousand years ago. We are pretty certain today that Homer didn’t wholly originally wrote the Illiad and the Odyssey. He belonged to this oral tradition and put it down into writing. Something that might have been seen as unnecessary at the time, for text was relegated to legal documents and treatises and court proceedings.

EDIT: Here’s a practical demonstration. Write down the lyrics for Mr. Brightside. Chances are that you know them by heart.