Most buyers of Mustangs are over 35, and want something that doesn't look like a trendy, Lime Green Scion, Eclipe, and Celica. Also, it is not like the T-Bird, a $40K two seater. I know 16-25 year olds want "futuristic", but then they end up buying used Civics, since they can't afford insurace for sporty cars. (Rich kids are a small minority.)
The 500 is not meant to be a "enthusiast" car, it is for the 80% of buyers who don't read car rags and memorize drag times. The top 10 car sellers are average family sedans, like Camry, Civic, Corolla, and Accord, not the "rocket ships".