It seems that Jobs took a trip to Japan in the 1980s and was rather moved to see everyone at Sony wearing a uniform. He was keen to adopt the same sartorial consistency at Apple. He thought wearing the same corporate garb would help Apple employees come together--something school uniforms never seem to quite manage.
Jobs discovered that the Sony garb was designed by the fine Japanese fashion icon Issey Miyake. So he asked Miyake to create, dare one even imagine it, an Apple vest for all of Cupertino to wear.
Strangely, Apple employees expressed aggressively negative reservations about such a 1984-ish suggestion. "Oh, man, did I get booed off the stage," Jobs told Isaacson.
The Apple CEO and Miyake, though, stayed in touch. Jobs' enthusiasm for a personal uniform remained undimmed, so he asked Miyake to make him some of his classic black turtlenecks. He received "hundreds of them."
Jobs then offered Isaacson a quote that now seems painfully poignant: "I have enough to last for the rest of my life."
Many will feel that Jobs understood that the more he was seen in public, the more he felt he ought to project a consistent brand image for his own personal identity.
Which still leaves on question that might perplex one or two people--even Miyake, perhaps: Why the Levi's?