I'm aware of some of those in major cities. Produce does not constitute the whole of one's daily diet (overwhelmingly). Hence, specialization.
Also, having these small produce-oriented grocers does not imply that people are doing daily runs. In my city I only see them in posh, upscale neighborhoods. In some larger metropolises like NY I've seen them also in less gentrified places, but they tend also to be specialty stores.
Groceries in cities sell meat and bread, etc often too, they’re no different than normal grocery stores, just not as big as a supercenter.. I feel like you’re overcomplicating this due to lack of familiarity. And sure, maybe you don’t go to the grocery store literally every day. Maybe you get two or three days worth, what’s comfortable to hold or to push in a cart. Sometimes you order takeout. This is normal stuff in places that aren’t rural areas where the only option is to drive 5-10 miles to a grocery store.
They're a fraction of the size. If average weekly needs and wants were met by those, that's where people in those neighborhoods would shop all the time. Everything else would be redundant. But instead they seem to fill a missing middle.
> maybe you don’t go to the grocery store literally every day.
Chicago, NYC, Lisbon, Berlin, Barcelona, etc. They all have their versions of these stores. You don't need to go anywhere else unless you want to for some reason.
Also, having these small produce-oriented grocers does not imply that people are doing daily runs. In my city I only see them in posh, upscale neighborhoods. In some larger metropolises like NY I've seen them also in less gentrified places, but they tend also to be specialty stores.