There should be 2 systems. One for needs and one for wants. We shouldn't have to compete for needs, and we shouldn't expect the things we want. An ideal system would definitely be a seriously regulated capitalism with an uncompromised safety net that we focus on with automation and AI. But, those with just want those without to die. In the end, they will lose.

Those who try to include all life when trying to determine justice: Should a man be executed for killing a fly? No? The fly has a short life span? The fly is small? All these rationalizations can be applied to you, by a creature that lives longer, is bigger, etc. #philosophy 

The social contract between all people around the world only has one requirement: Don't kill. From there it's those who don't agree, those that agree but have some reactive justification, and those that agree and don't kill.