There is a symposium in The Guardian on that question, here is my short contribution:
Thomas Piketty’s Capital in the Twenty-First Century has been a hit for several reasons, most notably the quality of the work. But I’d like to focus on a neglected reason why the book has found so much support, namely it appears to strengthen the case for redistribution.
Most previous commentators focused on income inequality. Bill Gates or JK Rowling have earned more than CEOs or authors in the past, while incomes in the middle class or lower middle classes are often stagnating below what previous generations could expect. That’s a labor market issue – namely that some individuals are not very much demanded by employers.
The obvious questions are then a) how can we make low-earners more productive, and also b) how can we improve education?
Perhaps most importantly, as these issues get processed by the public there is a common attitude – whether justified or not – that many of the lower earners are partially or fully responsible for their own plight. The egalitarians don’t tend to win these policy debates.
In the simplest version of the Piketty model, wealth grows more quickly than does the economy as a whole and thus the picture changes. The relative losers are no longer low earners but rather anyone who is not a capitalist. Any disparity is due not to their shortcomings in labor markets but rather to their lack of a high initial endowment.
Furthermore redistribution will work like a charm, at least provided the redistribution is enough to give the poorer individuals some capital to invest.
If you are an activist who favors lots of redistribution, the Piketty story is a lot easier to tell yourself and to tell your audiences – and that is yet another reason for its popularity.
The other contributions are by Brad DeLong, Stephanie Kelton, and Emanuel Derman, who cannot bring himself to read the book.