There are clear differences in vehicles, whereas most people stop at whatever gas station is closest because most gas is the same.
IMO, GM stopped making quality products sometime between my Silverado and my Beretta. It was probably when they stoped stamping "GM Mark of Excellence" in their keys
(yes, I still have the original keys for my truck on my key ring). Both my cars are alright, and not even below any other manufacturers, but there is a clear difference over that 10 years. Even though GM has supposedly started making quality cars again (at least the waranty implies it), it's hard to get past the late '90s and early '00 crap. Another problem is they don't listen to what the consumer wants.