Another industry that seems to get along well without intellectual property protection is the fashion industry. Brand names and logos are protected by trademark, but the design of clothing is generally not protected in the United States. [...]
At one time, the fashion industry did have a self-imposed system of intellectual property protection. In the 1930s, the Fashion Originators’ Guild prohibited copying among its members and urged retailers not to sell items from those who copied other designs. The guild was reasonably successful in these efforts. But in 1941, the Supreme Court held that its practices violated antitrust laws, and since then the fashion industry in the United States has had no intellectual property protection for designs.
That's from Hal Varian's column on needlessness of intellectual property rights (at least in some domains).