His departure, seemingly without warning, stunned the world. But Tim Cook's time had come, cut short by his perceived unwillingness to confront a technological shift that now has swallowed him.For a man who helped usher in Apple's communications revolution, it was the ultimate irony.More than 1.5 billion people across the planet feel completely dependent on the technology he pioneered, and, if not physically attached, consider their iPhone an essential part of everyday life.Add in another billion or so Apple products out there, from Macs to iPads, AirPods, and even the odd remaining iPod, and it's little wonder the devotion many…