As they are for households, then they suffer from exactly the artifact exposed by the article. Individual income inequality has changed hardly at all. Household inequality has changed a bit because of what I, if I may, term the “Bell Curve Effect”.
I see your point, but for most I think the "Gini coefficient" is a metric they can't understand. And even if they do, it's hard to penetrate the "it's unfair" meme.
I don't think there's any point in denying that the average for the top 1% (and the top 20%) has grown more than the lower brackets. It's done so mostly during the boom periods in the economy, because they risked their money to help fund the boom. Without that incentive for capital gains, that money would have been parked on the side: just like it is now. And there would have been no boom.
However, I think it's demagoguery to focus on the absolute amount, rather than the share of income. The top 1%'s share of national income has only doubled in the past 28 years, and their share of the federal tax burden has also doubled. As a result, the tax burden on the lower 80% has been reduced significantly.
The other problem is that all of these comparisons assume that income categories are static: meaning that someone spends their entire life in a particular category. A CBO study over a 5-year period found that isn't true: about half of the people in the lowest 20% had climbed into a higher category. In general, people moved up into higher categories, and new entries into the workforce filled in the bottom.... keeping the cycle going.