You're allowing perfect to become the enemy of good. People who buy luxury cars are not going to stop buying luxury cars. So the options are luxury cars that po

You're allowing perfect to become the enemy of good. People who buy luxury cars are not going to stop buying luxury cars. So the options are luxury cars that pollute the environment, or luxury cars that do not pollute as much. "The real green decision" is whatever is more environmentally-friendly than what you would have done otherwise.