What if its not "taxing the rich more" and instead, is "preventing them from capturing all of the productivity gains the economy is realizing"?
Because then we get into this real uncomfortable argument, don't we? About what ownership is? Because when you're taxed, people will say that's theft of what they've "earned". But the wealthy don't earn like everyone else. They earn as rentiers, of either land, capital, or intellectual property.
I'm suggesting the entire ownership model is going to need to be turned on its head. Otherwise, those who own what the rest of the world needs will continue to siphon wealth out of the economy, to the detriment of everyone else.