For me, I can see several different ladders leading to one direction.
(I am going to generalize. It may not be correct, but it'll help me get my point across)
You've got Chevy and Saturn at the bottom, with "Baseball, apple pie, and Chevrolet," and "Soccer practice, Starbucks, and Saturn." Both provide basic transportation at an affordable price; Saturn for people who have an image to consider :rolleyes:, and a Chevrolet for someone who wants something reliable and American.
Then, if you want to take a step up from Chevy, there's Pontiac for the people who prefer performance. For those who prefer bells and whistles, there's Buick. If you're a truck kinda person, you've got GMC. Saturn, being a more Euro kinda brand, leads into Saab.
If you prefer trucks, you've got an additional rung with Hummer. Hummer acts as the "Cadillac of trucks," for those who've got money and want to show it.
At the top of the ladder, you've got Cadillac. This is the brand to get when you've "arrived."