I grew up near a strip shopping center with a supermarket about the size you describe, a pharmacy, insurance office, barber shop, dime store (T.G.&Y., an Oklahoma chain), dry cleaners, liquor store, and laundromat. The year after we moved in, OTASCO (Oklahoma Tire & Supply Co.) built a store alongside the supermarket, about the same size as the supermarket. They sold tires, auto parts, bicycles, small appliances, sporting goods, and toys. They built shopping centers of this sort adjacent to new subdivisions built in the 1950s and 1960s, typically one at every junction of section-line roads.
Reminds me of a similar refit of an old A&P supermarket in Scarsdale, NY, which is now a (quite nice) 24 Hour Fitness: https://www.google.com/maps/@40.9992997,-73.8156547,3a,75y,136.66h,90.66t/data=!3m7!1e1!3m5!1sFWfkLTJEwharw2YvvqDbBA!2e0!5s20071001T000000!7i16384!8i8192
I grew up near a strip shopping center with a supermarket about the size you describe, a pharmacy, insurance office, barber shop, dime store (T.G.&Y., an Oklahoma chain), dry cleaners, liquor store, and laundromat. The year after we moved in, OTASCO (Oklahoma Tire & Supply Co.) built a store alongside the supermarket, about the same size as the supermarket. They sold tires, auto parts, bicycles, small appliances, sporting goods, and toys. They built shopping centers of this sort adjacent to new subdivisions built in the 1950s and 1960s, typically one at every junction of section-line roads.