It’s not just about losing history, but also mixing it with incorrect/wrong retellings of the story and fake news.
For example, you mentioned Homer, the writer of the Iliad and Odyssey who lived 3000 years ago. Homer’s existence is hotly debated, and even if he did exist, “he” probably didn’t write both poems. It’s far more likely that the Iliad and Odyssey were created as part of an extensive oral tradition by multiple travelling bards, who independently added, changed or removed verses; the story we know today as the Iliad is just one of many who happened to survive for a variety of reasons.
We also know very little of the broader trojan cycle (Cypria, Little Iliad, Sack of Troy, etc…) of which only fragments have survived. It would be as if, 1000 years from now, only the original SW trilogy survived, and only pieces or fragments of the other movies/TV series in the expanded universe remained - And to be fair, even this example is wrong, because it compares the Iliad/Odyssey to the “original” trilogy, but there’s no consensus about the relationship of the two Homeric epics with the broader epic cycle: as far as we know, they could have been created independently, and later edited to flow from one to the other seamlessly.