Tim Cook's legacy now rests on board tenure

Apple cannot just coast, however. Its overwhelming importance to memory suppliers and chipmakers has waned with the explosion of data centers. Artificial intelligence will lead to new gadgets that may threaten the dominance of its own. A fracturing world also makes selling handsets and other products and services harder. Ternus will presumably lean on Cook, who mastered supply chains and diplomacy, for all these matters.

It’s important he not become a long-term crutch, however. Walt Disney’s Bob Iger is a textbook case of sticking around too long. He handpicked Bob Chapek to replace him in 2020, but remained executive chair before stepping back in as CEO, with less success than his earlier run.

James Gorman, who helped clean up the Disney mess, provides a better template from his time leading Morgan Stanley. After refocusing the investment bank on wealth management following the financial crisis, he ceded power to Ted Pick in 2023, kept other seasoned executives from leaving and became executive chairman. Gorman then left the boardroom a year later.