The only way you can prevent feudalism is by preventing accretion of power. Otherwise, it's a positive feedback loop through and through - the rich get richer,

The only way you can prevent feudalism is by preventing accretion of power. Otherwise, it's a positive feedback loop through and through - the rich get richer, the powerful get more powerful. How exactly to do that is up for debate, and I see socialist democracy plus regulated capitalism as the most practical current answer. Unfortunately it's not a stable position and is prone to failing if any one side can't be kept in check by the others.