> human evolution (and survival) matters only until 14-40
I just don't think that's true. I think grand parents being around was important for human survival.
If it wasn't, if all that mattered was having the most kids, then why would women go through menopause? Wouldn't it be better if women continued having children until they die?
I think it makes sense that young people have kids (the sooner the better, faster evolution and less chance of DNA degradation)
Then they should live as long as possible to help raise their grandkids to ensure their genes survive.