BYMONEK
The reasons should be self evident - accountability, responsibility, and also the little phrase, "Chain of Command", a very unpopular phrase in these inclusive days but still laid down in the Air Navigation Order ( and that's a Law of the Land, not a Union agreement) and available for closer examination in Crew Orders!
By your logic the 35 year CSD should also earn more than the new CEO - you don't mean that...do you?