Competition between businesses is feirce, and most don't operate at a high profit margin. Voluntarily switching to more enviornmentally-friendly methods can be financial suicide, and most business owners wouldn't see it as making a big impact on the enviornment since other businesses would just use the old methods anyway. Most business owners would feel it's more important to keep their employees employed and their familys fed than to make the amount of difference to the enviornment that one less polluting company would be. It isn't as if gas-fueled cars were our only option. There are now electric cars, and there have been bicycles and buses for a long time.
Most people choose polluting cars because they are cheaper and more convenient.
For most people, choosing a different means of transportation wouldn't cost anybody else their job, or put our means of income at great risk. Before condemning the actions of others, try to ask yourself what it would take to get you to stop doing a similar thing. Federal laws usually do it, but not always. Attitudes are a hard thing to change. It isn't as if gas-fueled cars were our only option.