Interestingly, if you look at the list of the verified oldest people, only one is over 120 years (http://en.wikipedia.org/wiki/List_of_the_verified_oldest_peo...).
If I start another religious cult and claim that humans won't live for more than 130 years, am I suddenly more valid?
What exactly is your point here?
Given BCE life expectancy I think it's safe to interpret all these numbers as "poetically large" and leave it at that. :)
Infant mortality was real high and those lived long, lived real long. A lot of them died in epidemics and wars.
We also know from Roman records that we have only just reached their lifespans, and still they were healthy for a longer percentage of their lives than we are (infant mortality aside.) It's not unreasonable to think that even the Roman lifespan was a decline from that of earlier civilizations like the Hebrews.