Until recently, there was a straightforward path to becoming a top dog at a supermarket company. All you had to do was start at the bottom and devote your entire career to gradually climbing the rungs of a company ladder. Hard work, long hours, devotion to employer. Some 40 or 50 years later, you were at the top.
The problem was the ladder often didn't support people willing to buck tradition with outside perspectives and new visions. Retailers paid the price for that failing.