I don't think it's that simple, because the frequency of the shipments and amount of goods shipped would also decrease (although not linearly) since there are l

I don't think it's that simple, because the frequency of the shipments and amount of goods shipped would also decrease (although not linearly) since there are less people to account for. If both systems are equally optimized, would there be a difference? That said, in practice the "economy of scale" argument still applies and the inner-city store will overwhelming produce less carbon, besides the fact that a rural area may imply an increase in the distance good are shipped.