This is an extremely common phenomenon, upper middle class and upper class people tend to describe or think of themselves as middle class. Same with lower middle class too who are paycheck to paycheck.
Hedonistic treadmill and only comparing yourself to the people above you warps your perception. People like quote actually have NO idea how much money or wealth the median person has in comparison to them. The fact that they compare themselves to the top 0.0001% wealthy Kardashians to say they’re not “uber rich” is extremely telling.