For some people it is about price. For others it is about location. Some people even look for superior service. Each of these is a tactic that may be employed by a retail business to create customers.
Near where I live, Kroger dominates the area with four stores that are closer than any competing [food] store. CVS is a bit closer in two instances. Could one really shop for most groceries at a CVS? If one had very limited needs it is possible. For the 99.999% rest of us, we will probably have a supermarket or supercenter that serves our grocery shopping needs.
Location [access] is the biggest reason I shop Kroger for groceries. Each of the four stores is on a major road all within 1.5 miles of home. No matter which way I am coming from, there is almost always a Kroger to be found on the way home.
Where do you shop for groceries, why?