Those are pretty speculative dating systems too. And they base themselves on the literal ages of the people there.
There is, in no way possible, for a human to live beyond say 130 today. The oldest ever almost made it to his 121st birthday, and he was blind, deaf, and I think mute as well by the end. And the reason why life expectancy is so good today is through modern medicine.
Folks back in Jesus' day, on average, would have gone in their 50's or 60's if in a more "civilized" area and probably 40's elsewhere.
Those numbers merely show the decline of human-God relations due to original sin, nothing more.