It's more like class than caste, because it's possible to move between classes after birth. Modern advertisers are sort of similar to a priestly/censor class, in the same way that serial C-suite/board members are sort of like an aristocratic class.

Discussing that sort of thing is discouraged in the US, because it stinks of nepotism and conflicts with our culture's ostensible ideals of meritocracy and egalitarianism.

It's an easy mistake to make, because in order to obscure our society's important class distinctions, we make a lot of noise about other differences that people are born with, which feels very caste-y.