I actually saw the over representation of blacks in ads explained by a marketing experts.
Whites in studies on the subject don’t care about the race of the actors in the ads. They focus on the procuct. Blacks, however, do care. So it’s a win to put blacks in the ads due to black racism. The expert didn’t put it that way, but that’s the idea.
I believe another element in TV ads is the audience themselves; in my experience white guys are a lot less likely to watch TV than minorities or women, and because they make up a good portion of the workforce they are less likely to p!ss away hard-earned money based on an ad - or because some celebrity said so.
I’m not a high-tech person, but I’ll read reviews online before I buy something - couldn’t care less what goofy pitch they put on TV.