Naive self-interest is a characteristic of children. You didn't stumble upon some ancient wisdom of another culture, you just matured and established a family, which your instincts tell you to put before yourself.

The West is individualistic, but all that means is that individuals choose their circle of concern. Without any further guidance, that means that innate instincts about who is important (family, close friends) dominate, rather than a forced narrative about the collective.