For my neighborhood, I believe it's because the neighborhood didn't exist 3 years ago. So I agree I think it's a huge opportunity. The first HEB (grocery chain in TX) to open up in the neighborhood is going to make a killing.

For others that have existed for longer, sometimes the zoning seems to just be residential forever so sometimes you have to drive for a bit to get to the nearest "stuff". I think that's pretty standard for suburbia.

And then for yet others sometimes they're just too far out and too small of developments to make building a supermarket just for them financially viable.