Obviously if you take it very literally, every species on earth in the back of a homemade boat, the entire planet being wiped out, etc - it doesn't stand up very well. But I'd be willing to entertain the possibility that the story is the fossilised remains of an oral tradition that predates the written record - perhaps the loss of lands after the last ice age, etc.
FARGARD II. Yima (gamshêd).
And Ahura Mazda spake unto Yima, saying: 'O fair Yima, son of Vîvanghat! Upon the material world the fatal winters are going to fall, that shall bring the fierce, foul frost; upon the material world the fatal winters are going to fall, that shall make snow-flakes fall thick, even an aredvî deep on the highest tops of mountains. And all the three sorts of beasts shall perish, those that live in the wilderness, and those that live on the tops of the mountains, and those that live in the bosom of the dale, under the shelter of stables. Before that winter, those fields would bear plenty of grass for cattle: now with floods that stream, with snows that melt, it will seem a happy land in the world, the land wherein footprints even of sheep may still be seen. Therefore make thee a Vara, long as a riding-ground on every side of the square , and thither bring the seeds of sheep and oxen, of men, of dogs, of birds, and of red blazing fires.
Therefore make thee a Vara, long as a riding-ground on every side of the square, to be an abode for men; a Vara, long. as a riding-ground on every side of the square, to be a fold for flocks. There thou shalt make waters flow in a bed a hâthra long; there thou shalt settle birds, by the ever-green banks that bear never-failing food. There thou shalt establish dwelling places, consisting of a house with a balcony, a courtyard, and a gallery. Thither thou shalt bring the seeds of men and women, of the greatest, best, and finest kinds on this earth; thither thou shalt bring the seeds of every kind of cattle, of the greatest, best, and finest kinds on this earth.
Thither thou shalt bring the seeds of every kind of tree, of the greatest, best, and finest kinds on this earth; thither thou shalt bring the seeds of every kind of fruit, the fullest of food and sweetest of odour. All those seeds shalt thou bring, two of ever, kind, to be kept inexhaustible there, so long as those men shall stay in the Vara. There shall be no humpbacked, none bulged forward there; no impotent, no lunatic; no poverty, no lying; no meanness, no jealousy; no decayed tooth, no leprous to be confined, nor any of the brands wherewith Angra Mainyu stamps the bodies of mortals. In the largest part of the place thou shalt make nine streets, six in the middle part, three in the smallest. To the streets of the largest part thou shalt bring a thousand seeds of men and women; to the streets of the middle part, six hundred; to the streets of the smallest part, three hundred. That Vara thou shalt seal up with the golden ring, and thou shalt make a door, and a window self-shining within.'
https://en.wikipedia.org/wiki/Zanclean_flood https://en.wikipedia.org/wiki/Black_Sea_deluge_hypothesis
The biblical account isn't the oldest version, however. So it seems unlikely that that version is correct, whereas older versions were wrong. Although the older known versions weren't very believable either, so it's possible something might have happened, but it doesn't seem like there's really much to go on beyond "there was a huge flood, and a few people survived." Which definitely did happen, repeatedly.
That's the part that fascinates me - it seems obvious that the OT gets more realistic the closer events get to the written record. But some of the parts we write off as unrealistic could be the remains of stories as old as the human race. If the flood myth describes the end of the ice age, that would mean you and I are sharing an oral tradition 10,000 years old. I find that a lot more exciting than how factually accurate it is.
I agree with you, although there's a large contingent for whom whether or not it's factually accurate is the most significant concern.
A person who lived 175 seasons (each 3 months long) would be 44 years old. A person who lived 900 moons would be 74.
It’s happened to spacecraft, http://www.cnn.com/TECH/space/9909/30/mars.metric.02/
So I'm left with three thoughts that don't necessarily agree with each other.
One, is that it seems fairly obvious that there's some transition from oral histories to written histories; and the closer the event was to the written record, the more realistic it gets (which we also see in the OT).
Two, is that there's a lot of crossover between Sumerian kings and Gods, so it doesn't seem inappropriate for the oral tradition to imbue kings with god-like properties.
(As an aside - I can easily imagine that in tens of thousands of years from now, with fragments of records remaining, someone could argue with a straight face that the early space-agers actually believed Queen Elizabeth was immortal and semi-lizard. This is obviously comical, but does illustrate the risks of an oral tradition.)
And three - the possibility that there's intermingling between these two traditions? Or that there's some cultural factors here where we're seeing the effects without the causes (ie we're not seeing why it was popular to assign these characteristics to ancestors, only that they did so).
But to come back a little more on-topic - Sumer is also where we get the sexagesimal (base-60) numbering that we still see in time & angles. So when comparing units, there could be some mistranslation between different number bases at some point.
Oh my god I'm picturing bojack horsemen as the last surviving digital media; not so different from ancient hieroglyphs of animal heads and human bodies...
Robert Best wrote "Noah's Ark and the Ziusudra Epic: Sumerian Origins of the Flood Myth" ( https://www.amazon.com/Noahs-Ark-Ziusudra-Epic-Sumerian/dp/0... ) in which he translates the numbers back into Sumerian using the incorrect numbering system and then retranslates them using the correct numbering system. He ends up with not only ages that make sense, but it also fixes the unevenness of the Biblical ages. It also sorts out the Kings List numbers.