Class is more than just income, education, and occupation.
It factors family background, upbringing, lifestyle, social affiliations, network, and values.
You can make $30k/year and still be considered upper class if you were born into an upper class family.
You can make $5mil/year, but if you were not born into the upper class, the highest you can attain is upper middle class at best, granted you have all the accoutrements of that class.
For instance, Oprah and Tyler Perry would be considered black elites. But they are not considered black upper class. We have political elites, academic elites, entertainment elites, cultural elites, etc. They would fall within one of those classifications. But being an elite =/= upper class.
The term black upper class is typically reserved for the group of black folks that are the descendents of the black families whose money originated during Reconstruction, the period right after the abolition of slavery. Or if you go back a little further, the black families that received land, education, or some type of inheritance left behind from a wealthy white slave owning father.
Most of the wealthy people we see in the US are actually upper middle class.
Class can be nuanced and I don't think most people actually understand it.