My mum never owned a car, we walked, biked, bus'd or train'd every day of my life. Because I was used to it and don't have a lot of money, I don't own a car either. I don't know what exactly you want me to do to give them less money, but what I do know is me walking everywhere every day has influenced exactly 0 people to do the same, and it's affected global carbon emissions by such a small fraction it can barely be measured.

It's not relatively small, it's essentially non existent, and there's no way as an individual to force others to give up their conveniences, any more than an individual can have the government ban all fossil fuels.

How much profit do you possibly think Australia provides to BP and other companies? How much of Australia doing business with them contributes to their global emissions? Because the fact is the entirety of Australia could return to tribalism with no modern technology and it would barely move the needle on either global profits or global emissions. Even a country that has 5% global emissions wouldn't achieve much by going to 0. It's near meaningless.