If you’re trying to solve inequality through tax policy alone, I wonder what the effect would be of having the top tax rate vary with the Gini coefficient. The idea being that the wealthy can theoretically reduce their tax burden if (and only if) they figure out how to use their economic power to reduce inequality by other means.
Partly—but depending on how much you want to prioritize redistribution vs revenue, you could adjust the tax/Gini curve to set the equilibrium wherever you want.