Why should that matter. One Vote, One Dollar Tax. Equal effort from all to make the goverment work.It would never work. It would be a disproportionate burden on lower income people.
If you focus on the burden you will have one idea of fairness. If you focus on the individual, each citizen must give an equal amount, you will have another idea of fairness.
Our current tax system is some amalgamation whether through consumption tax or income tax of that although it is currently fashionable to claim that the rich need to shoulder more of the burden.
BTW, I am not advocating anything just highlighting the unfairness of taxes in general.