Gross inequality is not a feature of capitalism per se, it is the feature of our current implementation, specifically the current banking system. This is due to a number of factors, the main ones being bankers being the first in line to obtain newly created credit, central banks central planning of interest rates, bank fixing of market rates like LIBOR, massive fraud and government handouts to the banks. All of the above can be fixed without having to tax those that create real wealth in the economy, however that isn't going to happen as the banks have far too much influence in politics and even if they didn't changing the situation without collapsing the current system seems impossible at this stage.