There was an article in Road and Track about how the current 20s crowd doesn't care about driving and wants techno-transportation. That may be mainstream, but Camaros are not mainstream cars, they are niche cars.
GM should think about cross shoppers buying BMW 3 series coupes, Golf GTIs, Audi coupes, along with the usual Mustangs and Challengers. In my view they need to have an American (ie not Euro or Asian) offering in that mix to stand out. Mainstream buyers don't care about rear wheel drive either.