I don't agree with your 30 years lifespan argument. The average of 30 years was always done taking into account a high degree of child mortality. Meaning that

I don't agree with your 30 years lifespan argument. The average of 30 years was always done taking into account a high degree of child mortality. Meaning that you either died before you got to 5 years old, or you easily got* to the ripe age of 55. Average 30, but very different lifespans. Also, many biological features are stable until 55, for example male strength with an adequate training. It is after 55 that everything starts to fail. What's unknown territory is living more than 70. * disregarding external factors like wars.