I think the idea was brought up because of capitalism. Marx believed that the more people would seek for profit, the more they would want power. He thinks that because of capitalism, there is an uneven distribution of wealth. The rich classes can earn more compared to the working class. The working class can only earn base from the service they have offered. Although capitalist systems are freer compared to the communist societies, Marx believed that communism is better because people in the society are equal in terms of labor and wages received