Flicking through my notes on the sermon series that started this blog: that on Genesis, I had recorded the speaker's remark: the purpose of the genealogies is to find the 'serpent crusher', that mentioned in Genesis 3:15
And I will put enmity
Between you and the woman,
And between your seed and her seed;
He shall bruise you on the head,
And you shall bruise him on the heel."
Their work is to connect the arrival of the serpent crusher to the events that gave rise to the fall, curse and promise, and to direct us to undoing of our basic fear, that of death.
If there is no historical thread between the serpent crusher and Eve, that is, if the events of the garden are mere story...myth, then there is no point to the serpent crusher being in historical continuity with that which he will crush; and death is not undone, because death is in our historical context, not in a story world.