While Capital in the 21st Century has raised a lot of eyebrows it has not been put into the proper perspective. Picketty's book makes one interesting claim, that r grows faster then g. In other words the return on capital grows faster then the economy. This is not An important issue in an autocratic feudal society. The peasants have no real income or wealth and little political power.
However in a pluralistic liberal democracy the rising income inequality is a real issue. It is because inequality has the potential to undermine democracy as the wealthy increasingly find ways to "buy" elections on the one hand and to maintain economic and political power on the other. We are witnessing this today right in front of our eyes. However, what is really at issue here is not that wealth and income are concentrated but that the concentration undermines capitalism as rent seeking replaces entrepreneurial activity and innovation. Picketty's answer to the dilema of having r grow faster then g was inadequate and all know it. However that does not underestimate the underlying problem of what to do about it because it is not sustainable.
"Why Philanthropy Matters" offers an answer to the Picketty puzzle and it in in pat an American answer. America has faced this question and debated it for 300 years. America wanted rich people but it did not want a class structure. In other words we wanted to become rich but we did not want to see wealth stay in the same hands. So America invented philanthropy. Philanthropy is the solution to the Picketty conundrum of r being greater then g. Philanthropy does two things. First, it recsonstitutes wealth and second it creates opportunity for others by investing in education, universities and research that increases growth. So philanthropy simultaneously increases g and reduces r.
This uniquely American solution to the age old issue of wealth also gets around the question od redistribution that no one really likes..