wealth = income - consumption
In the U.S., we tax all three: general income tax, consumption tax (e.g., sales tax), and wealth tax (e.g., property tax). Taxing any one has an effect on the other, and a discussion about one is relevant to all others.
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))