Walmart and Menards are not in the same category of retail. Both stores are present in virtually every place that Menards operates. The fact that Arkansas is the home base for Walmart is completely immaterial. If you look at the map of Menards stores, you will see that they are clustered, undoubtedly to allow the distribution system to be in place before expansion begins. If Menards ever makes it to Arkansas, it will be because it is the logical next step from a neighboring state.
As for other grocery names, all that I can say is I'm glad Wisconsin-based Menards stepped up to create a model of a 400-store Midwestern chain that was iconic in five states until the 1980s. Minnesota-based Department 56 did likewise in 2001. There is too much of an East Coast bias for model production, so it's nice to see a manufacturer add some variety to the mix.