Yes, a whole new can of worms...
This was recently a hot topic here at BWHQ. In addition to the cultural/historical reasons list above, there is a game mechanical one.
To reflect how rare Read and Write were, I wanted to impose a skill point penalty. I made them two separate skills -- doubled the cost of the skill for a character who wants to become a scholar -- to show try to reflect this rarity.
You'll notice that the Elves and Dwarves actually have standard Literacy skills -- their Script skills -- to reflect the higher order of their cultural evolution.
It's not a perfect solution, I know.
What would you have done?
"Athos—Porthos, farewell till we meet again! Aramis, adieu forever!"
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