Tim Cook made Apple unshakeable, now John Ternus has to shake it

There is an office at Apple's old Infinite Loop campus that has been locked and dark since 2011. It was Steve Jobs's, and when Tim Cook took over he never moved into it. Fifteen years later, nobody has.John Ternus is expected to take Cook's office at Apple Park. Cook kept his distance from the man he replaced and spent fifteen years being compared to him anyway. Ternus starts at Cook's desk, with Cook down the hall. He is staying on as executive chairman, has told colleagues he will keep running Washington and Beijing himself, and said as much in the note he sent staff on his last day in the job: he is not leaving Apple, he is stepping away from a role he loved.Every part of that is sensible.