Reposting here, since you created the thread while I was typing this up
I don't want to get off on too much of a tangent here, but as sex and death are two of the main driving forces in society I think they're inexorably linked.
You're right. People are forgotten in time. That's why we have to make our mark on the world. We have to build things, or create things, that will live on when we're gone. And more than our marks on the world, we also have to make our marks on people. They are the ones who will carry our memory as far as they can. They are the ones who will be most influenced by who we were, and live differently because of how we affected them.
For instance, I'm not the same man I would have been had I never known Densetsu. I'm a better man because of his influence. And I hope that people will say the same for me when I'm gone.