Tend to agree, but my training partner is doing everything he can to improve traps - he is 6'2" 98Kg and only have a 15 1/2" neck size; its funny!!! because he is pretty well rounded but its noticeable
If you spread your lats when you deadlift it would be quite hard to shrug it effectively I would have thought. I used to lift by pinching my shoulder blades and squeezing my traps. That really worked them, but isn't correct really.
Has he tried neck specific exercises with a head strap and cable machine or tried neck bridges? You can do quite a lot of neck work resisting your hands.