Becuase handling better and going better is only one part of the story, if it was all that mattered why not buy a Caterham? When you are selling mass market cars to mass market consumers you have to get so much right, interior and exterior design, equipment, quality, image, etc etc.
It's no good having a car that JUST does one or two things becuase its horrifically out of date.
Thats true if you are a sub £1k banger beardy or something but if you are the sort of person who buys brand spanking new cars then you are not going to want to put up with early 90's quality and design for 2005 prices are you?