If you have a Minecraft world that's somehow limited to a small space, it is possible to create a sustainable economy. The ever-essential wood can grow back and animals can reproduce. However, if players have goals other than survival in mind, they can get depressingly destructive.
One Minecraft experiment put 30 players in a 350x350 world bounded by indestrucible blocks. Play only occured when all players were online. After wood became scarce, the players divided into four different gangs: The Brotherhood, The Dwarves, The Axe, and The Merchant's Guild.
- - -
Strip mining began as factions raced to secure rare quantities of diamond. With diamond pickaxes in hand, obsidian mining became possible. A nether portal was built, but quickly broken down by The Brotherhood to act as a foundation for their castle.
One pair of players saw the danger signs earlier than the others. They built a base attached to a mountain, waited until grass had spread onto their dirt platform and then smashed the mountain to leave a floating, sustainable fortress. From their platform they raided the world below, destroying vital blocks. “From the first week in they began systematically depleting resources in a way that would set the other players behind. Glass windows were broken, trees and saplings were stolen, massive amounts of dirt were farmed”
Here a fortress protects a small patch of grass, a vital resource for food which comes from animal spawns.
The amount of non-cooperation is discouraging, but at least players banded together at night to hide from zombies. The player who organized the experiment, WordworksExperiment, asks what the experiment can teach us about human nature:
The experiment was up before more testing could be done, but I ask you. If the walls were torn down one day and the players were free to the unlimited resources of Minecraft how would they react? Do you think they would work together and try to keep all the resources balanced or would they play the same way without regard for their environment or each other? Though in Minecraft's infinite world it would be impossible to destroy everything, do you think the disaster would slowly re-occur? I think this experiment has been a successful statement on the human condition and human interaction with the environment.