Why did all those socialist communities fail in America?

If the society where you live doesn't permit secure private ownership of property it will stagnate and probably fail. This holds true not just for socialist communities, but for non-socialist societies where people's property rights can be easily destroyed by fraud and corrupt officials (think any hell hole where there is no way you can prove you own the land your house is built on). If the effort you put into improvement and enterprise is easily forfeit, why make the effort at all? Working for the greater good may make some rich kid NYU poli sci major feel warm and fuzzy, but it doesn't work for the rest of the world.