the make the CVs longer because the differential isnt lowered, if you did lower it the problem is solved.......the angle is more important.....at 2" its probably borderline of not needing anything but GM probably found it cheaper production wise to just have longer axles vs making new brackets to lower it a an inch or so.......you wouldnt think that would be the case, but seems like it is as most bigger lift kits just use drop brackets.....longer CV in a bad angle is still a bad angle, at 2" not really a concern , at 4"-6" and up it is
GM probably gets the half shafts for same cost as the standard ones so doesnt cost anymore to build than standard truck.....however if they had to make frames different or brackets than that does add cost and time between 2 models....slower production also adds cost, so just an idea and idk if this is true