>At which point you can be happy that the rich person is voluntarily paying the 3 cent fine instead of the 1 cent parking fee.

No, because the issue here is not like a fee, it's about breaking the law and how you should be punished for it in order for it to deter you. A more apt comparison would be "you can be happy that the a rich person is voluntarily paying 500$ to park on top of a crosswalk. In this case you want to deter the person from doing something that harms others, not just to make them pay for it, which in this case means either a fine indexed to income or jail time, so it hurts you even if you are a billionaire.