Let's play around with the idea as it were real, if humans believe their able to extend life using nanobots and new robotic bodies why can't we have this discussion for fun? Let's call it Science Fiction if you want, could the Aliens that started life on Earth tinker with human age if they desired because they wanted to see how long humans should live and at one point in time they hit the maximum benefit before longer life brought a diminished return to overall mankind?
One interesting theory I read is based off evil, if the most wicked human beings were allowed to live for 200-900 you can imagine how bad things would get. Since we are all prone to the Devils temptations under this version of history, could a human being who made it to ruler have furthered the End of the World through their genius? Imagine if the greatest scientists ever, hit their prime in their 90s, they lived on to be 300-500 years old could some bad guys live long enough to pick the best and brightest humans from the Race to further their wicked intentions bringing us all under their domination? Remember, I am talking Science Fiction like L. Ron Hubbard who wrote about Xenu living for Millions of Years buried on Earth in a Volcano! Please give me the courtesy and add your own ideas how humans could live long lives through Science Fiction if that's how you want to label our this thread! :)