With all due respect, I don't see how your post is actually related to Piketty's book at all, in the sense that it isn't even discussing the same subject, let a

With all due respect, I don't see how your post is actually related to Piketty's book at all, in the sense that it isn't even discussing the same subject, let alone engaging with Piketty's actual analysis! Your post seems mainly to be about income inequality, particularly pointing out that it's often transitory and different over lifetimes than in single years. Those are interesting points, but Piketty's book isn't about income inequality. The book is mainly about capital holdings and what they do in economies over time. With issues such as: returns on capital vs. labor; concentration of capital holdings; persistence of large capital holdings over time; ratios between economies' capital holdings and rates of income; etc. Even looking only at the political part of the book (which is not the biggest part), his concern isn't about income inequality, or even inequality in general, but about wealth inequality that can maintain itself persistently. He predicts (with some caveats) that current trends suggest large holders of capital will increasingly be able to maintain and increase their capital holdings, producing stable multigenerational stocks of wealth akin to those seen in 18th and 19th century Europe. Whether right or wrong, that's not at all the same an issue as inquiring into things like income ratios between Google's programmers and janitors. He's interested in a more structural level about e.g. the differences between an economy where extant wealth equals 10 years of annual income, versus one where it equals 2 years of annual income (he argues that in the latter case existing wealth stocks are less entrenched, because they in effect represent fewer years "head start" over current income earners, and that this ratio explains some things about the relative roles of capital in 19th-century France vs. 19th-century U.S.).