I think people are misunderstanding your point here. This is an evolutionary advantage because it facilitates the passing of skills and knowledge. Because of that it is, like you said, directly linked to why we get old instead of, for instance, having two dozen kids and dying at 20 like rabbits might. Folks that kept grandparents stayed alive more than ones that didn’t.
I would say that humans have grandparents due to the nature of human mating and offspring.
Yes, they can help care and give wisdom. Directly linked to why we get that old.
Edit: apparently, other primates have grandparents too.
I think people are misunderstanding your point here. This is an evolutionary advantage because it facilitates the passing of skills and knowledge. Because of that it is, like you said, directly linked to why we get old instead of, for instance, having two dozen kids and dying at 20 like rabbits might. Folks that kept grandparents stayed alive more than ones that didn’t.
Thanks, you explained it better.