Inherent in the human nature is the desire more. It seems that no matter how much we have, we always want more. Some societies suppress this natural human desire in their citizens through religious ideas such as fatalism or through social caste systems. Others simply control every aspect of their citizens' life through governmental and societal controls. Eventually, the human spirit is crushed enough that they no longer attempt to achieve more than is allotted to them.
One reason that capitalism works for us is because human nature always seeks to achieve and attain something more (with individual exceptions of course.) It relies on human ambition to spur growth. This plays out in the church as well as individuals often seek only their own blessings, their own experience with God and their own prosperity.
We have become so successful as a nation that the majority of us now enjoy great wealth, compared to the rest of the world. In reality, we are drowning in our own affluence. We have a multitude of "comforts of home" that shield us from the outside world. We shield ourselves from pain, discomfort and poverty of the world by the things we collect and the lifestyles we protect. This growing materialism is one cause for the church's downfall in Western society. We can no longer relate to a suffering world and its needs because, in comparison, we no longer have real needs ourselves. If we are not careful, the words of the Old Testament prophets will be spoken to us. "how I have been grieved by their adulterous hearts, which have turned away from me, and by their eyes, which have lusted after their idols." Ezekiel 6:9