Now we are into an entirely different subject. Stop trying to change the subject.
IMO, state sovereignity has nothing to do with a state taxing it's citizens, note: NOT subjects, for purchases not physically made in that state.
Others may disagree with that and probably have since you say it's legal for the state to do that.
Private property rights have nothing to do with this. Nothing at all.
Its is very simple. If the state is barred from taxing its citizens on out of state purchases it essentially bars it from taxes its citizens at all. For example car and other large purchases would all be made out of state. Then the same logic would extend to the income tax. Your concept would fully undermine the tax system of each state and force states to either appeal to the federal government to establish a federal system or force them to enter into a pact whereby they create a nationalized system of taxation.
Trust me, you don't want to establish the system you suggest because you would not like the result.