GMC has all the govt and Construction contracts, it's always been more of a commercial brand than a public brand, besides the quality of GMC's is excellent so there's no need to end it.
It's been well known by dealers for a while now that this is what's going to happen to pontiac. Also look forward in the future to several lines getting dropped by GM such as Saturn and Saab. And i believe hummer is going to be dropped, which wont be a huge impact on their military contracts cause the govt doesn't have a high demand of humvee's anymore.