Comment by OkayPhysicist

In-n-Out is cheaper than McDonald's. A preference for McDonald's isn't a class issue, it's a taste issue.

The popular disdain for family dining comes from people who don't want to sacrifice food quality for table service. Olive Garden isn't competing against fine dining, it's competing against fast casual restaurants. And that's far less of a class divide than a generational divide: restaurant dining as widely available phenomenon is a relatively new concept, with it being a relatively rare luxury for the Greatest Generation. This put a level of perceived prestige on being served, which the family dining restaurants managed to reduce the cost of substantially the latter half of the century.

With ubiquity, though, the novelty wore off. Young people who grew up regularly eating restaurant fare aren't particularly impressed by table service, and thus for a given price point, on average, Millenials and younger tend to choose a fast-casual restaurant with better food quality over a family dining establishment that has to cut into their food quality to pay for table service.

What you're perceiving as a class divide is a urban/rural divide, where trends of all sorts (including this one) lag a decade or two behind in rural areas relative to urban ones.