AZ is like any other mass-market retailer.
Local store stock is selected to maximize sales per square foot.
That selection will be based upon what moves given the demographics of the area in which the store is located.
I have been in most of the auto chain stores in this general area, and there are good and bad examples of all of them, from my point of view.
The old time parts stores were great and also fun.
The counter people were knowledgeable, and usually had their own intersting old cars and projects. Many of them raced or did autocross. They were true enthusiasts.
These stores are a dying breed, unfortunately.