That could be but I’d need to see data to support it. There are endless scenarios that could play into disposable income. I’ve read that
more young people live at home and buy luxury brands, for example. While a couple right at the cutoff for top 10% with 4 kids and a mortgage on a townhouse might not have anything left over for vacations. I can say with confidence that the population has increased by over 100 million people or so, and the number of people in the top 10% has increased proportionately. On disposable income, I have no data one way or the other.