You asked why the cars are not selling better...just my 2 cents but I think it's mostly the Chrysler name. At above $30K, you're no longer talking about basic transportation, and most folks who are willing to shell out those kind of dollars for a car can probably afford even more dollars...so they would rather have the Porsche, Mercedes, Lexus, etc. names. Also, at this price class, many reviews rate the Nissan Z as having a bit more power so speed demons are going for those (which do sell well).
From what I've read and seen, the majority of folks ultimately buy the Crossfire for its looks as the deciding factor...where it's so beautiful that they're willing to stretch the budget for it (but typically can't stretch the budget farther for that Porsche). The power and handling that the Crossfire does offer is icing on the cake (and plenty of it). Of course, there are some folks that can afford this car five times over, and I still think that ultimately they love the styling.
As for styling...it does have a unique (some say over-designed) style, and as a two-seater, it's not everyone's taste. Hence, not huge sales.
But that's just fine with me. One of the best things about it is having a unique car...it does get the looks and you can't help but smile.