I can't find my previous post on this, and I haven't recalculated
the time from the bible, but I beleive that these
alternate cultures had on a matter of a couple hundred years
to develop ... from originators with first hand knowledge
of the power of the one god ... and some of the elders lived into
their hundreds still producing offspring.
We have second or maybe third generation believers developing
a polytheistic, Pharoah-is-god culture with vastly different
world-view to Noah's children in only a couple of hundred
years ... not to mention the populational support required
for the culture.