My guess is that the driveshaft and half shaft suppliers couldnt deliver cost effective units that could safely and durably handle 200 mph.
Theres a LOT of force going through a CV axle in general, then add the fact it has to be able to hold itself together being rotated at an absurd speed AND to do it repeatedly.
Im sure there were plenty of suppliers that could build and deliver the units they needed, but not at the cost. My guess is that this is a bean counter related decision.
I think the 13-14 boys and girls just got one more feather in their cap.
Has a 13-14 actually been clocked doing 200mph stock? I know the Hellcats have.