Have you ever heard the saying, "the most important things in life are free"? I think that thought is more important than we think. Lets take an environmental perspective.
First lets define the most important things in life. We can only live a few minutes without air and a few days without water. Food we can do a bit better and maybe make it a week or more. We need shelter and clothing, love and friends, but that's not the direction I want to go.
Industry also has demands. In order to make a product, you have to start with a material. Plastics, metals, cloth, etc, industry pays money for these raw materials so they can make them into products that we will buy. I don't care how simple you try to live, you will inevitably buy something made of a material that has value. We call these sources of value natural resources.
The point I'm getting at is that water and air are among the most abundant resources that we have and because of that they have little monetary value. Because they have little monetary value industry pollutes them since it won't affect their bottom line. Air and water are unique in the fact that we have to share these resources. There may not be a monetary value, but air and water are of infinite value because without them our lives will cease. The most important things in life are free... maybe we need to change that so that people will recognize the value of what they are destroying.
Likewise with the STUFF that we have, the most important and valuable stuff is intangible: my wife, love, freedom, etc.