The transfer of corporate power from battle-hardened builder to professional manager is always tough. Howard Schultz, who turned Starbucks from a handful of Seattle coffeeshops to a global behemoth, has pulled it off twice. At the turn of the millennium he passed on the chief executive’s mantle to an heir, only to return to shepherd the firm through the global financial crisis of 2007-09. He then abdicated once more in 2017. After stepping…