The argument against killing Buick is always that they sell well in China. But they do that just because of the name, there's nothing special about the cars. So just limit Buick to China and rebadge Holdens and Cadillacs, like they're doing now. (Holden's not in danger, is it?)
I like(d) Pontiac because they at least claim to make performance cars. They were just starting to actually do it, too!
What will the fast cars be when (if) they start making them again?
I blame everyone who didn't like the new GTO, that was a fabulous car.
(...although part of that is that no one liked them, so they're really cheap :D)