That's the difference between a democracy and an oligarchy. In Chile, the government tells the people and companies how much to pay in taxes. In the United States, the corporations tell the government how much they will pay in taxes.
Neither is an oligarchy, either. And while corporations and individuals of means have a disproportionate amount of influence in American politics, Chile is not immune from the same phenomenon; it just takes a different form.
But I agree with you in spirit - wealth should not be a factor in how much influence someone has in a democratic system.