You're right that by leader I mean more "ruler" in the biz-self-help context, but I would suggest anytime people are buying articles of clothing all in the same

You're right that by leader I mean more "ruler" in the biz-self-help context, but I would suggest anytime people are buying articles of clothing all in the same colour (compare Wodehouse's "Black Shorts" movement) it's obvious what they are doing, no matter what word we use to describe the person who is the focal point.