In what way doesn't it work?
It taxes wealth creation instead of wealth consumption (spending). That doesn't work for those who need/want to create wealth because the same congress that turned the income tax into such a monstrosity has stolen the money American workers put aside for retirement.
Not only have they stolen everyone's retirement money they are preventing people from creating wealth by taxing the growth of capital.
Uncle Sam: "gimme some money to save for your retirement."
Man: "what happened to the money I gave you last week?"
Uncle Sam: "I spent it."
Man: "maybe I should put some of this money into the stock market."
Uncle Sam: "nah, too risky."