I live in a rural valley.
FAMILY DOLLAR & DOLLAR GENERAL are literally across the street from each other.
A gallon of milk at Family Dollar is often over $1 more than a gallon at Dollar General.
Dollar General store is cleaner & has a happier staff.
I was told this was because the chains were started by ex-spouses. The ex-husband would invest in traffic surveys, local market potential, stuff, and build a store after extensive research. Then the ex-wife would then build the competition right across the street.
Same with Lowes and Home Depot. Bitter divorces that expanded shopping choices for us.