You give them enough free market so that the most intelligent get more money and create more wealth and you give them enough government intervention so that the Gini-coefficient of national income distribution is not that high.
'K. But remember that every intervention punishes those who have made good decisions, and rewards those who have made bad decisions.
People will see this, and act accordingly. Incentives matter, after all. How long do you think it will take before you've set a ceiling and a floor, so nobody tries too hard, and nobody worries too hard about failure? How long before those two meet?
Just because taxes exist and just because the tax system is progressive doesn't mean the richest won't want to earn more money. So we'll reach no ceiling. The same for the "floor theory". I don't like extremes, I'm not defending communism nor neoliberalism.