That was a good survey of some conventional, incremental steps that could be taken. One point I could nitpick would be your definition of capitalism, which I think must include some reference to an economy (if not to say society) dominated by large-scale enterprises (‘Big Business’). We had a market economy in the U.S. before capitalism developed here. (Yes, slavery was legal everywhere, but — not to minimize it morally — it was not economically definitive outside the South.) Also, the Scandinavians and other European nations, which according to your map have the same amount of economic freedom as the U.S., have tamed the capitalist beast rather well — and such an approach could do better yet if the U.S. did not exist as a haven for beastial capitalism.
I have developed a more far-reaching solution by applying the justness of political democracy to the capitalist economy (“Extending Democracy to Our Capitalist Economy to Transform Our Society” here on medium.com). (For the record, I do have an M.A. in economics.) A sketch of the nuts and bolts of that approach to bringing justice to capitalism is here in “A Cure for the Ills of Capitalism.” That approach could be extended even further to eliminate exploitation — without setting any limit on income or property or wealth. The whole shebang is summarized in “People for Tolerance, Unite!”