Cheap knock-off spur innovation in the fashion industry, but for specific reasons.
The paradox stems from the basic dilemma that underpins the economics of fashion: for the industry to keep growing, customers must like this year’s designs, but they must also become dissatisfied with them, so that they’ll buy next year’s. Many other consumer businesses face a similar problem, but fashion—unlike, say, the technology industry—can’t rely on improvements in power and performance to make old products obsolete. Raustiala and Sprigman argue persuasively that, in fashion, it’s copying that serves this function, bringing about what they call “induced obsolescence.” Copying enables designs and styles to move quickly from early adopters to the masses. And since no one cool wants to keep wearing something after everybody else is wearing it, the copying of designs helps fuel the incessant demand for something new.
The situation is not necessarily easy on designers, who have to keep coming up with new ideas rather than being able to milk a trend for years. But it means that in the industry as a whole there is more innovation, more competition, and probably more sales than there otherwise would be. And the absence of copyrights and patents also creates a more fertile ground for that innovation, since designers are able to take other people’s ideas in new directions. Had the designers who came up with the pinstripe or the stiletto heel been able to bar others from using their creations, there would have been less innovation in fashion, not more. (Source)