Ice cream was initially a dessert only the rich could afford. Now it's for everyone. Except, of course, in communist wonderlands like Cuba or Venezuela...
Chips and crisps used to be a delicacy. Can't see how that would be exclusive to the rich though, the components (potatoes and hot fat) are (and were) pretty commonplace.
Deep fried anything used to be a luxury, because calories were expensive, and a whole pot of boiling oil is a lot of calories.
IIRC, southern fried chicken in the US descends from cooking styles that only the aristocrats of western England could afford. Which their 2nd sons (or rather, their 2nd son's cooks) brought along to Virginia.
https://www.mashed.com/220283/the-strange-story-of-ice-cream...