Are you aware that "ALL CULTURES BEGAN SUDDENLY" and were fully developed? A long preliminary period is not supported by archaeology. Before cities on earth, there was nothing. There was no transition whatsoever between the ancient civilizations and any primitive forebearers. They were at their peak from the beginning. :

...Great cities, enormous temples, pyramids of overwhelming size. Colossal statues with tremendous expressive power. Luxurious tunnels and tombs. Splendid streets flanked by magnificent sculpture, perfect drainage systems. A decimal system at the very start. A ready-made writing, already perfected. A well established naming system (in which each Pharaoh had as many as five names). Society already divided into specialist classes. An army, civil service and hierarchy minutely organized. A court exhibiting all the indications of well-defined precedence and form. Egypt came from a clearly established civilization.

The only conclusions that can be drawn from the evidence is that,1 Each of the first civilizations appeared suddenly, already fully developed. 2) That a connection existed between them. 3) Their footprints led back to the Middle East mountains where Noah and his family left the Ark.