These are excellent questions, and one should take them on vigorously outside the shower. And consider related questions, like: Why did most Westen Hemisphere cultures (all, afaik) had NO alphabet. Some had counting symbology. and some rudimentary quasi-standard pictograms, but no real alphbet. Or why did the Romans use the complicated system of Roman numerals? And were the picto-glyphic wrtten languages of Ancient Eygpt and also that of China preceded by a phoentic alphabet, and if so why was it replaced?
Then there are meta-questions: can these questions be answered, and to what degree of accuracy? The past is always befogged! Some think they discover some stones, or ancient papyrii and solve it. Take a paltry amount of artifacts, and queasy bits of "dating" technology and combine arrogance and we'll have many false certainties paraded as utter holy truths.
