One of the things that people miss is the inability of people to pass information over a wide range before the printing press.
You could have invented Quantum Mechanics in Ur and no one outside of a small group in a small area would have ever known.
Excellent point.
I've read that the reason the American Indians know/knew so little of their history was that all the knowledge was kept and passed-down by the memory of the elders. The European diseases preceeded the advancement of western civilization by decades and these diseases usually killed the oldest and youngest first.
When the westerners arrived asking who built such and such...no-one knew. The elders had all died and the knowledge was lost.