I'm pretty sure alot of the stories of the old testament came from Babylon and Persia, after the Hebrews went into captivity (political move). Look at it as wandering people in a desert are not going to write things down. Permanent records are hard to keep on the move. Its a survival trait for tribes. So its easy to add a written account later on. The Hebrews had access to written accounts in their captivity.
As for Abraham, who is supposed to of been born in Ur (modern day Iraq), the land the Israelites are claiming now, just seem to be the land Abraham went over from coming from Ur. Now Abraham is supposed to have putten the stone in the area of Mecca (According to traditional Muslim sources)... Like to see the Israelites claim that land....
That is the thing about educated people they can sit down and think through all the errors in their writtings, kinda like a programmer debugging a program....