Slant 6 Split exhaust

If duals were the hot ticket, more power, torque and efficiency, why didn't they just do it from the factory, they were already chasing economy and power levels via other ads putting these motors head to head with GM and Ford 6's? Crazy bolts ons advertising huge power gains...If you think it would cost Mopar too much, I gotta call BS on that. Whats another casting (they already had the Hyper-pak exhaust castings) and a piece of pipe as opposed to a $450 A/C option or a $227 FM radio? Just use a 2.25 head pipe and exhaust. Sometimes Mopar got it right out of the box, but I still dont understand the 1 7/8 head pipe. Maybe the backpressure observed increased torque down low?