It could simply be brand recognition. Visitors to a city will know which chain stores to visit to get what they need, glossing over (or avoiding) unfamiliar sto

It could simply be brand recognition. Visitors to a city will know which chain stores to visit to get what they need, glossing over (or avoiding) unfamiliar stores. So mom&pop stores get local customers, while chain stores get local PLUS just-visiting customers; multiply by months and years.