Possibly, but I can’t find any data that would adjust for household size. Either way, you can see the top two deciles running away with the fruits of the past few decades.
Average household income is simply average per capita income multiplied by average household size. (This would not be true for median, but I wanted to illustrate how simple it is).
Household size has been decreasing over the last 50 years (less people per family unit), and household income is therefore growing more slowly than per capita income. It's still growing though.
No, I can't; if the lower income households have been splitting their earnings into a greater number of households, a growth per person would be masked by a drop in total income per household.
To use figurative numbers, if a couple earns $30k each, then they split but both get a raise of $20k, the household average drops from $60k to $50k despite the large salary raises.
If that is true for 80% of the population, then that is similarly a cause for concern.
While you are correct that change in household size could be muddying the income numbers, I would say that the difference in behavior between top 20% and bottom 80% must reflect something driving the two apart.
https://www.advisorperspectives.com/dshort/updates/2019/11/2...
Median doesn't tell enough of the story for what most of the population is experiencing.