What will become a more common story across the United States – in both rural and urban areas – can be seen at this link.  General Motors really, really wants its dealerships to have a broader brand base for buyers to choose from as GM attempts to individualize each of their subsidiaries.  GMC, Chevrolet, Cadillac, Buick, Pontiac, Saturn, Hummer, Saab all compete in one way or another.  Bringing brands under one roof with cars that are distinct would dispose of the competition and breed a strong team approach.  

In other words, “Oh, need more truck than the Enclave? We have a Yukon Denali right over here.”  In addition to that theory comes clear cost savings and greater long-term viability. 
Thus, in Albertville, a place I’ve never heard of in Alabama, Howard Bentley Pontiac-GMC is now Howard Bentley Buick-Pontiac-GMC.  No; that’s Bentley as in the owner’s last name, not the British hyper-luxury brand.  
Wayne Bentley’s dealership will typically have an extra 40 cars on the lot.  Having started out with Oldsmobile and Pontiac in 1988, GMC came online and the Oldsmobile sign disappeared with… well, Oldsmobile.