I'm watching a similar phenomenon here in West Virginia where Krogers are still closed because of strikes. In one area of town a Food Lion opened up a few years back right next to a Kroger.
Folks were striking back then in front of the new Food Lion (I think it had to do with non-union construction contracts, but not sure). Not sure if this was part of the reason, but it seemed the Food Lion parking lot was always near empty while Kroger's was packed.
I often commented with friends about how it seemed that Food Lion most certainly must be losing money, and how is it they could stay in business. But now the tables have turned, and with Kroger's lot empty, I've never seen so many cars at Food Lion. I now wonder if the Kroger re-opens, if maybe their loyal customers have already switched allegiance.
In my experience, folks become comfortable with a certain grocery store and learn to become familiar with the layout. Going to other stores becomes a chore as they are unfamiliar with what is where. I know that my girlfriend, once loyal to Kroger, is now quite pleased with the local Giant Eagle. And she has the striking workers to thank.