It is not irregular for oral societies in general, not just in the Middle-East, to be able to pass down their sacred history and related memories and sayings faithfully.1
The idea here is that, in oral retellings over time, fieldwork suggests the stories more tend to lose information and grow less vivid. [Forthcoming]
Individuals in the Mediterranean (or Greco-Roman) world tend to be very proficient at remembering.
Elaboration on these arguments are forthcoming:
Some very experienced field-workers can testify to the incredible memory capacities of oral communities. For example, here one scholar comments on the work of Bailey and King:
Over and above simply passing down their history carelessly, perhaps among individuals, members of oral cultures rather took a collective approach in remember that tended to involve several quality-controlling mechanisms.