[briandh]

> you can be certain that there is enough demand for food to support at least one grocery store...

People need food, but grocery stores aren't the only place to get it. I can't speak about Detroit specifically, but it is common for inner city neighborhoods to only have fast food restaurants and "corner stores" -- glorified convenience stores that make most of their money on tobacco, alcohol, and lottery tickets, but happen to have some food as well. They are a far cry from what most people would call a grocery store (even compared to smaller ones like Aldi, Trader Joe's, or Piggly Wiggly).

Now, there may be a grocery store 15 minutes away by car, but that distance becomes significantly more troublesome when you have to take a bus.