This cost to the individual meant that one would have to learn how to be part of the community to benefit from the cooperated problem solving of large issues outside of personal capabilities. This required to be a valuable member (useful) for the community and for the most part, that meant the community would grow without any particular member having a lot more or less than the next. This worked in such small groups.
Wow what an interesting proverb...i agree with this and true word one head can not carry a load to the head...they must to agree with each other and have a good understanding...the role of exchanging by barter might be included...i inspired by the story @tarazkp