I think that one thing you have to understand is that the mythos communicates an event that was real and historical. Did God create the world? Absolutely. Did man sin and fall short of the glory of God? Yes. Is all man under that same curse of sin? Agreed.
Is Genesis 1-11 an accurate historical representation of these events? No.
An event may be real and yet transmitted through mythos for various reasons. We see this every day.
A single satirical cartoon can out-punch a lengthy opinion article in the daily newspaper, regardless of how well-written the article may be.
Many people have read George Orwell's Animal Farm and know what it means for some people to be "more equal" than others, even if they would never go near a historical treatise on the Russian Revolution with a ten-foot pole.
Many guys call themselves (or are called) "Romeo"s while knowing full well that Romeo is a fictional character.
A play with a village, a witch, and a scientist can win the first place in a small school drama competition where a lengthy reenactment of the Dark Ages (complete with the flaying of Hypatia!) would have bored everyone to sleep in half a minute.
Are any of these forms historical? No.
Does that stop these forms from transmitting the truths manifested in very historical events? Not at all!
Genesis ultimately describes historical events in a mythical way which, while perhaps obscuring their historicity and authenticity to the modern mind, bring out every ounce of spiritual truth which those historical events were loaded with.