Let me explain.
Take an example of a father. He usually gets up early. He gets ready for work. He thinks about his boss. He thinks about his coworkers. He thinks about the clients. In addition, he thinks about his family; he thinks about his spouse and children. He even thinks about his dogs and cats. What's more meaningful to him than his family? Nothing else.
Same goes for the mother, if not more so.
In short, we think about others all the time. Our self-interests seem like an afterthought. If there is any self-interest at all, it's to achieve heartsease or peace of mind knowing others will be fine.
Economics is important for a higher standard of living. It's how resources can be efficiently allocated. But the way people make decisions is ultimately based on how they can obtain the most benefit for others in their everyday lives. They are vastly more important.
In Chapter 10 of The Art of War, Sun Tzu sums up the main objective of a leader:
"The general who does not advance to seek glory, or does not withdraw to avoid punishment, but cares for only the people's security and promotes the people's interests, is the nation's treasure."