I don't think this is accurate. Piketty throws a big wrench in any assumptions which rely on increases in the average being disseminated widely throughout the economy. Economists have mostly made this assumption before Piketty, and the field hasn't really caught up to accounting for this effect. Globalization seems to be one of the major drivers of capital's advantage vs. labor in capturing a disproportionate amount of growth of late.

So, wealth distribution is a controversial topic in economics right now that is highly relevant to the conclusions that can be drawn from econometric models that deal with global trade.