If it's zero sum you can design a system where everyone gets three sane amount. That's what strict monogamy does for mating, and you can easily imagine some "ev

If it's zero sum you can design a system where everyone gets three sane amount. That's what strict monogamy does for mating, and you can easily imagine some "everyone is equal" communism-like system. In practice that doesn't work, and the most successful "common good" systems instead ensure the disparity is limited and access is as equal as possible (e.g. not everyone can be wealthy, but the wealthy are not too rich and anyone had a chance to become rich instead of needing rich parents; or everyone can only have one married partner at a time instead of people who can afford it amassing big harems and not leaving any partners for the rest; or anyone can become famous, and famous people pushing their kids into fame is looked down on)