The Parkinson Law (not to confond with the disease) wants that, the bigger a company gets, the more this company hire unskilled but overpaid people.
Simply because the top management fears the arrival of powerful rivals. And the best way to avoid that is to hire incompetent people.
The best way to suppress any will to climb up in the hierarchy is to overpay them. Then the top management are reassured and find permanent tranquility.