Because: "Oldsmobile was the oldest surviving American automobile marque, and one of the oldest in the world, after Peugeot, MAN, and Tatra."
No Oldsmobile and there would not have been a GM or Chevy.
I had one of the last full size Auroras with the NorthStar derived V-8 and it would cruise in absolute comfort and stability at 120mph all day long. With it aluminum suspension and equal length half shafts providing zero torque steer it handled like a dream. But in their ultimate stupid wisdom GM downsized it. GM has a long history of killing off models just when the got them right.
To achieve anything, you must be prepared to dabble on the boundary of disaster.”
Sir Stirling Moss