ya but its also a commentary on shoushika, the japanese declining birth rate issue
Adding to this, on top of the declining birth rates, all of the young people that do get born are all moving to the city for jobs, so you have a lot of old remote towns slowly becoming abandoned over time.
This dagashiya is probably in a place like that. I don't think all the kids in the photo are hers; more likely, a lot of them were local kids who hung out at her store but grew up and left town, and if any of them had kids of their own, they're not growing up here, so the town is empty.