>If people in a community have to drive three hours for food, then there will be enough demand that someone will open a grocery store. When there's an economic vacuum left by a closing superstore, other, possibly smaller, stores will come back and fill it. It's simple economics.

Real life doesn't always play out like simple (simplistic) economics.

E.g. sometimes nobody will do the investment to build one for years.

Or it will much smaller and more expensive that a Walmart, but enough to stiffle anybody opening a competitor.