> Well, it's a bad thing for 90% of American households no matter how you look at it.
It sounds like you believe that if the ownership share of the top 10% went up, then the average wealth of the bottom 90% went down. The latter does not follow from the former. Both can have seen increases in wealth.
Your "precise statement" was a manipulative statement, for which both the question and answer are meaningless. Just because you state a question does not mean you get to dictate the discussion. Growth of income is one thing, but the far more important thing is wealth inequality, and the U.S. has one of the worse in the world, especially for a developed nation. As wealth inequality goes up, more people die, more people suffer, etc.
Here's the equivalent of your statement: If I throw a penny into a fountain at the mall, has the wealth of the fountain gone up or down?
Here's more realistic and relevant discussions on the relative gross of the lower classes:
Wealth for the lower 90% has gone up but that is nearly meaningless when the cost of living has increased much greater than any of those wealth increases.
This is precisely correct, ironically downvoted. The 90%/10% is a distraction, the pool of wealth is nearly unlimited as long as we have natural resources (energy, materials).
This trend will continue until resources are no longer exploitable, or people trying to enrich themselves created artificial scarcity or restrict their trade.
This is false. The concentration of wealth directly correlates with increases of death, starvation, suffering, etc. Inequality is by far the most important measure. "Growth" of income is effectively meaningless on its own without relative comparisons to the other classes in your own country and the significantly higher increases in the cost of living. If you look for the narrative you'd like, you can certainly find a number in isolation supporting it. But that narrative falls down when you look at the whole picture.
It sounds like you believe that if the ownership share of the top 10% went up, then the average wealth of the bottom 90% went down. The latter does not follow from the former. Both can have seen increases in wealth.