Here's a list of 10 vehicles that symbolize, one way or another, Detroit's failures over the past three decades. In a couple of cases, they talk about decent cars that were kept around for too long, or modest platforms that were marketed the wrong way.
But, on the other hand, there's the Pontiac Aztek and the Chevy Vega.
I think it is silly to include the Taurus on this list. that was quite a good car. Otherwise, it is pretty good. These models weren't the only thing GM, Ford and Chrysler were selling at the time, but they represent very great and costly mistakes.