The land was quickly overgrazed and eventually became worthless as villagers exploited the communally owned resource. When assets are publicly owned, there are no incentives in place to encourage wise stewardship. While private property creates incentives for conservation and the responsible use of property, public property encourages irresponsibility and waste. If everyone owns an asset, people act as if no one owns it. And when no one owns it, no one really takes care of it.
Public ownership encourages neglect and mismanagement.
Much of the economic stagnation of socialism can be traced to the failure to establish and promote private property rights. As Peruvian economist Hernando de Soto remarked, you can travel in rural communities around the world and you will hear dogs barking, because even dogs understand property rights. It is only statist governments that have failed to understand property rights. Socialist countries are just now starting to recognize the importance of private property as they privatize assets and property in Eastern Europe. The economic atrophy that occurs under socialism is a direct consequence of its neglect of economic incentives.