I have very different style from Steve Jobs but I do like his "uniform" approach of having something simple that works for many situations and wearing it frequently. I buy many copies of the same outfit and wear in a lot of situations. Why waste time in the closet every morning (or evening) trying to pick out an outfit. I still mix it up for situations out of the normal every day though and I buy many colors of the "standard" pieces so I have some variety.
Because if you're not a famous billionaire, everybody judges you based on your looks. And if you look like a cheap nerd, it's really hard to become CEO, or any other important job for that matter. It's not that hard to understand, really. I assure you that when he was selling computers or searching for investors, when he was unknown, he couldn't afford to look like that.
Looking like a cheap nerd doesn't help anybody. You can be successful despite it, at most.