> We already get taxed multiple ways. I pay income tax and sales tax

Shouldn't we also not do that?

Suppose you pay a 25% income tax and then a 10% sales tax. You're paying the same amount, almost a third of your income, as you would with a 47% sales tax. Which to begin with misleads people into thinking their rate is lower than it is, and on top of that incurs the significant overhead of needing two independent collection infrastructures.

Why isn't it better to just pick one?

Do I get a refund the next year when the stock drops due to an executive scandal?