Not grandfathering new features is not unheard of in the car industry just as it is not in others, especially with tech stuff. Retrofitting and back updating things can always introduce new issues and are sometimes ignored as the price of forward evolution in the car business. It would not be unusual for there not to be a straight forward manufacturer upgrade path for CarPlay when it finally does come to the Genesis. Has happened to all cars as new features come out, sometimes in between model years. Its also not unusual for the communication about these new features to be poorly handled - BMW and MB do it all the time.
As far as the Sonata getting stuff first, that may be pure economics - the Genesis while sort of a flagship, is not the sales machine the other lower priced cars are and the competition at that level is more intense.
As far as the Sonata getting stuff first, that may be pure economics - the Genesis while sort of a flagship, is not the sales machine the other lower priced cars are and the competition at that level is more intense.