This same life-cycle reasoning applies to income. After all, it's income that results in income taxes. Yet, even though I have probably read at least 70% of Krugman's popular writing over the last 12 years--and probably over 80% of what he has written on income and taxes--I can't recall his ever discussing the life cycle of income. I think he talks about high-income people as "the rich," thus not making the distinction between income and wealth. If he had talked about income over the life cycle, he would have noted that the data at a point in time show more inequality than exists over the life cycle.
So here's my challenge: prove me wrong. Provide a link to something in the popular literature in the last 12 years--NY Times, etc.--that has Krugman pointing out that there's a life cycle to income.Actually, Paul Krugman is usually at pains to deny any such thing, for one recent example;
Multi-year measures of inequality, it turns out, aren’t much lower than single-year measures. How is that possible, when many people change income quintiles? Because they’re usually moving short distances on the income scale. A lot of people move from, say, the top of the second quintile to the bottom of the third quintile or vice versa — but such moves are trivial in terms of their true income position. Big moves, jumping more than one quintile, are much less common; yet it’s those big moves people have in mind when they talk about ,mobility.