Sometimes God provides answers and examples in front of us, but they don't become obvious, and we end up in tangential discussions.
We have a scientific / medical phenomenon of "Progeria" as a living example that God can accelerate the aging process such that our lives are reduced by 1/10 of that of a "previous" or "normal" generation. Most children with Progeria don't make it to 20 years old, and by 10, they resemble someone who is in old age....
If we believe that Noah's ark was real, and that Noah's decendents were the only ones left on the planet after the flood, why can't we also believe / accept that those same decendents carried a Progeria-like "mutation" that accelerated the aging process in everyone AFTER Noah? Just like we have examples today of people who are genetically "destined" to live 1/10 of the lives that others live, why couldn't Noah's decendants also live ~1/10 of 950 years? This was done to fulfill the psalms ("and their years shall be 70, etc"), as well as the Biblical suggestion that due to our sinful state, God had to "cut our years" in hope that this may help us choose to repent.
Of course, there are some other examples later on of people exceeding the new theoretical maximum of 120 years (Symeon the Presbyter who received Christ as an infant, for example, or the 7 youths of Ephesus who helped prove the Resurrection was a real event), but these rare examples are God's exceptions for specific purposes.
Giannis