Depends where you are. Food deserts exist, even in relatively affluent countries. The range of goods at a supermarket is different in Bath (affluent) to Maerdy (poor).
Bath, being a major city, has far more residents and visitors than Maerdy, a small rural village.
My guess in Maerdy is that the residents probably drive somewhere (Aberdare?) with a supermarket. I'm not sure I'd live there without a car...