If you look at the normal ordering of GM cars they put constraints on orders from time to time. They plan and order based on expectations, just look at the Z51 package on the Corvette as an example. I'm not saying you won't be able to order the car, but the dealership will not have the allocations to get your order to go through. Uplevel cars like the Redline are promotional cars that normally get produced in limited quantities for lots reasons, limited parts, special training, warranty issues, etc.
Bottom line, performance cars are a niche market item. The Kappa platform offers a low-priced vehicle to a select market segment. Pumping high-end performance into it makes for good automotive PR, but is not really good for large production numbers. As the Asian car manufacturers have shown making lower priced vehicles in large numbers is what can really boost the bottom line.
You sell cars that people can buy and enjoy all the while keeping your overall costs at a minimum. We have a saying in auto parts business, performance parts cost twice as much and wear out twice as fast! This is one of the reasons why the sport compact car industry is so big, mo money and mo money keeps getting spent by those caught up in it. Selling the performance aftermarket parts makes money for those companies, but manufacturers tend to shy away for various reasons when comes to putting them on from the start.