"Steve didn't ever code," writes Wozniak. "He wasn't an engineer and he didn't do any original design, but he was technical enough to alter and change and add to other designs."
This is a characteristic that we see referenced time and time again in Walter Isaacson's biography on Jobs. He was perpetually retooling his employees' work, never shy about having them change it or otherwise improve it based on what he knew would work.
Nonetheless, it's odd that Jobs himself never learned to do the hands-on work he asked his employees to do. Today's big tech moguls, like Facebook's Mark Zuckerberg and Tumblr's David Karp, cut their teeth writing their own code.