You want to be exclusive, but that should be by price- not cutting your potential buyers in half. It turns into a numbers game I can't imagine them winning. What % of Americans who drive stick can afford the Viper, broken further into people who would prefer the Viper over other cars with a bit of power at around the same price point.
I just don't buy it will lose it's brand if they offered an automatic variant. The Hellcat doesn't lose it's brand or exclusivity because it offers an automatic variant. Yet it has overlap in a similar market- people who want a powerful American car..... I agree that they should continue to offer all of it in Manual as well. I just think they'd increase sales if they gave an option.