Tim Cook’s job was to make Apple boring—and he did. Cook, Apple’s chief executive officer, is stepping down after 15 years in the role. He had succeeded Steve Jobs after the visionary co-founder of Apple Computer Company left only months before dying of pancreatic cancer in 2011. Since then, Apple has grown in market value by 2,000 percent . It has also transformed into a staid, if immensely effective, firm that sells people glass rectangles , wireless earbuds , and, sometimes, computers . This