there is also the possibility that there was literal angels, giant hybrid man/angel types of 20' stature, and that Noah really was like - what does it say, 400 or something?

i haven't got a satisfactory theory yet for the strange longevity numbers in these old texts, the conventional ratio theories just don't quite work for me, and when you understand what a pole shift does to the landscape the "no stone left upon another" imagery suddenly comes into focus

is it possible that humans did literally live into their multi-hundreds at one time, and due to the degradation of DNA and adoption of sugar based diets the lifespan decreased to what was warned about after the expulsion from the Garden? 

it would be very difficult to guess at all, as it is genetic science is still pretty nascent and longevity is not well understood, we at best have an estimate that 150 years is possible with current knowledge with optimal treatment

and if all the fossils they know about were literally buried as little as 6000 or maybe 12000 years ago, and everything else before that is entirely lost, and these examples are extremely rare cases, then all bets are off, if you ask me

can't say yes or no, only that there is stories, and that hypothetically it is possible, given the right genes that we are not aware of