Piketty's tax goes into effect only for wealth greater than a certain amount. The goal is to target people who are paying insufficient income tax, because they

Piketty's tax goes into effect only for wealth greater than a certain amount. The goal is to target people who are paying insufficient income tax, because they are so wealthy they can avoid having taxable income. So we'd start the tax at assets over $20-100M. Normal people are completely unaffected by such a tax, since they already pay a high effective tax rate on their income (normal people generally cannot avoid income tax like the wealthy can). I didn't follow your argument about offshoring, since a wealth tax taxes all wealth regardless of it's location. So unless your parents left you a $20M mansion this is irrelevant