Waffle House managers, in my experience, are heavily sourced internally. (Or at least used to be)

This ensures you have a pipeline of new managers when someone moves on, as well as benefiting from far more experience than hiring externally.

Furthermore, while there may be higher paying jobs in a nearby city, there certainly aren't in the same area.

There are Waffle Houses at the intersection of two state highways. Which is to say, places where they're the only business there.