> Why should that obligation be proportional (or progressively proportional) to the wealth you have and not to the resources you use

It is proportional to the resources you use in every case where that is possible. It is nonsensical to say "Well, you used only 2% of police time this year, so that's how much police-tax you'll be paying", not least because it is impossible to put a "usage" on the benefit of having police in the first place. Where it is possible, like how much land you own, you are taxed proportionately.