In the US, fried chicken has very specific associations - it's a classic marker of African-American ethnic food. So it might signify "up-and-coming", but for a very different reason, reflecting racial and ethnic displacement that comes with gentrification in historically-black neighborhoods.
I think you're probably right, the inverse is seen in the US.
In the South fast-food fried chicken is sometimes a marker for not-yet-gentrified areas of a city, but often it isn't. Fried chicken is an ingrained cultural tradition of the south, for both whites and blacks, and if you count any place selling fried chicken in your analysis you're actually likely to see more fried chicken in richer areas. At least that's my anecdotal observation. I live in a section of town that's becoming gentrified and while chains like Zaxby's and Krystal are slowly disappearing, but pretty much every "fine dining" and even casual dining (i.e. one step over Olive garden) place that has some southern-cuisine related riff serves fried chicken
