> No, income - consumption is net increase in wealth. Those are all flows. Wealth is a stock. Wealth taxes are periodic taxes on the value of the stock, income taxes are taxes on the flow.

You're introducing periodicity, which I did not have in my simple model. Maybe a more complete model would be:

  Wealth_N = Sum {i=1 to N} ((Income_i - Consumption_i)*CapitalGrowth^(N-i))

Where N is some period like a year. Here, we can tax wealth, income, consumption, or capital growth. Regardless, it's silly to think of any one in a vacuum when considering tax policies.