Doing what you wanted the Challenger would not be available another two years. It would have cost Chrysler developement monies it dosn't have.
ORIGINAL: Billionaire
Dodge skimped on every product development cost they could. They reused the Charger chassis instead of creating a new, lighter one. They reused the charger interior instead of making one like the concept. They use the same paint colors as the Charger & 300 instead of buying extra painting equipment for high impact colors. So all you get that's new is the body. And also Dodge loaded the Challenger up with many off-the-shelf options which cost them nothing to develop. Maybe they got a bit of extra profit by sticking in all those options.
In order to bring the Challenger up to the full potential that it should've had, you'd have to take apart the whole car and find ways to lighten it and rebuild it, then put in a whole new custom interior to make it look a lot like the concept or something cool, and then put on a high impact paint job. The it'd be the way it really should be.