The belief-transmission game is rigged so that we must believe that children and money bring happiness, regardless of whether such beliefs are true.
This doesn’t mean that we should all now quit our jobs and abandon our families. Rather, it means that while we believe we are raising children and earning paychecks to increase our share of happiness, we are actually doing these things for reasons beyond our ken.
We are nodes in a social network that arises and falls by a logic of its own, which is why we continue to toil, continue to mate, and continue to be surprised when we do not experience all the joy we so gullibly anticipated.