Edit: Changed title to be more accurate.
Also here is the summary from Wikipedia on what Post-scarcity means:
Post-scarcity is a theoretical economic situation in which most goods can be produced in great abundance with minimal human labor needed, so that they become available to all very cheaply or even freely. Post-scarcity does not mean that scarcity has been eliminated for all goods and services but that all people can easily have their basic survival needs met along with some significant proportion of their desires for goods and services. Writers on the topic often emphasize that some commodities will remain scarce in a post-scarcity society.
Numerous different systems. If you want to look at modern, developed economies, Worker Co-operatives are smaller, Socialist entities that have far more equitable distribution, happier workers, and more stability. If you want a more Libertarian approach, EZLN doesn’t seem to have very high disparity, a bulk of the wealth is owned by the Workers, though they reject terms like Socialism. At the risk of being called a tankie (I’m not, I am incredibly critical of more centralized Socialist projects), even the USSR had far lower disparity during it’s time than Tsarist Russia or the current Capitalist Russian Federation.
The answer is for Workers to share the Means of Production in a democratic fashion, as opposed to having petite dictators focused on accumulating Capital.