The problem is building a stable system. You can have high taxes on the rich, but they will always use their riches to lobby to have them abolished. And even if

The problem is building a stable system. You can have high taxes on the rich, but they will always use their riches to lobby to have them abolished. And even if you don't have an elite ultra-rich class and massive income equality, the nature of liberalism (in the classical sense) is this will always eventually happen through the upward flow of wealth. To have a system that won't destabilise itself like this you would need a radically different economy, but I don't know how.