Yeah, the differences of supermarkets and distances in US and Denmark is quite big. We have four different supermarkets to choose from within this radius of 800m, three which are considered "discount" and one where you can get more luxurious goods which also have their own baker and butcher. I live in a small city of ~3000 people.
So I tried to make a small map and unless we go on a trip, my daily life is within this circle with a radius ~500m
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Boomer's experience would describe any "well-water" area of the US. Where I'm at, one example would be between Frederick and Germantown MD.
But once you're in a suburb city, the stores become frequent in reoccurrence in smaller radius. It's a driveable radius. Whole Foods, Safeway, Giant (local), Harris Teeter, Aldi.
Then you have the over priced "pharmacies" like CVS and Dollar stores supplementing the grocery stores for food.
Full service is more the norm than the exception. It's Aldi that is running on fumes(and their food is noticeably shitty enough that I, who usually doesn't really care where I buy, am wary of anything on their shelves).
There is some YMMV depending on how early a place is developed. The older a place got run over to construct a neighborhood, the more likely things are sprawled out.