Just finished Piketty's Capital in the 21st Century. His central claim is that the ratio of capital/labor increases as the rate of economic growth decreases because the rate of return for capital remains constant, and, he claims further, the growth rate will decline through the rest of the century as the population rate (the rate, not the absolute population) declines.
He recommends a tax on wealth/capital. But if he's right that the rate of growth will decline ceteris paribus, seems to me his wealth tax is not the only option: opening the borders should slow wealth inequality. Open borders w/naturalization would also counterbalance the political influence of wealth, Piketty's underlying complaint against wealth accumulation.
His tax could happen in Europe, but not likely here in the US. How would a push for immigration fare as a means to grow the economy? With an alliance of business with immigrants? After all, Piketty's prediction is a ratio, not an absolute quantity of wealth or its buying power. r>g holds when g increases, even though the ratio of wealth-income decreases. It would be a win-win for business and immigrants. It should not hurt unions in the long run either, although in the short run it might hurt a lot.