I wish the article would communicate more about how WaHo does this. I see they tend to stock their stores with generators, but is that the only thing? Does WaHo have longer shifts, reducing the need for staff missing shifts? Why is WaHo a better indicator than other services, like public transit?
As a southerner who has also pondered this, I think it's simply the basic nature of the menu and local nature of the employees.
Food is basically just pre-made batter, eggs, potatoes, and processed meat; all of which holds well and only requires limited refrigeration. Staff is pretty basic crew: Cooks and customers can order directly at the register if waiter isn't available.
Add to that a culture of staying open at all costs and there you go.
They have jump teams that come in and help get things back up and running. Since the training of the staff is standardized, jump team members can staff the restaurant and get it back up and running while the regular employees take care of personal matters.
Because 1) it's standardized beyond local / state political footprint, and
2) it's measuring basic availability of resources like water, electricity, natural gas, but also availability of food items like eggs, meat, bread. Plus labor.
And 3) in extreme cases, whether the (relatively uniform) building still stands and is occupied/usable.
In much of the Waffle House footprint, public transit is nonexistent or minimal and would not serve as a good indicator. There are certainly exceptions (Atlanta comes to mind), but in general, no.
