The Creative Juices, they are a-Flowin'

People will wear the ugliest things, if only they are stamped with a well-known brand name. They will pull out of their closet some tank top from the 80s simply because it is emblazoned with "GAP". It helps that these people live in Kentucky, so we don't have to think about them.
But rich people (who don't live in Kentucky) will choose to wear some out-there outfit, knowing that it cost a couple thousand dollars, just so that we are all aware exactly how rich they are. If something is expensive enough, it can be as ugly as a lap dog (actually, probably accompanied by a lap dog) and still be deemed wearable, only so that people passing by go, "oh, I saw that on McQueen's runway, but I didn't think people would actually wear it." But the wearing would then not have been in vain: the passerby knew that it was Alexander McQueen, and therefore knows that the wearer has lots and lots of disposable income.
Some people may actually wear some potentially hideous stuff in an acceptable way (see Carrie Bradshaw, circa '97). These people are bold, cutting-edge and daringly fabulous, and they look at all us J. Crew devotees and probably chuckle at our cowardice.
Four posts ago I referenced the Lego-ish Balenciaga heels of s/s '08. They're probably the ugliest things you could find outside of the uncensored pics of Britney's vagina, but their design is not about wearability (the shoes, not the vagina). It is about statement-making art, symbolism, publicity, discussion, or maybe it was a drunken bet. They can only be pulled of by high-fashion, and in its world, they are unabashedly Balenciaga. No one has a problem with couture dresses shaped and styled like sleeping bags (Viktor and Rolf, a couple years ago) or with huge sunglass headdresses with cartoon eyes pasted on them (Marc Jacobs, s/s '08).
True, blatant, non-arguable ugliness can only be appreciated in high, high fashion. To infringe upon the copyrights of Missoni, Prada, or DVF is expected, because the clothes don't stand out in a crowd (well, they do, but only to people with brains). But to completely copy a look by an avant-garde designer is risky.
I give you... The Balenciaga version:

And the Steve Madden version:

First of all, you're bound to get caught, and sued. Secondly, anyone who knows fashion will look at the maybe 10 people who will wear these Steve Maddens, and laugh in their face.
Probably fewer than 1000 people will actually wear a pair of those authentic Balenciaga heels, and half of them will be celebrities who were paid to do so. So who will buy these knock-offs by Steve Madden? They are not expensive. They will not be confused for the Balenciagas, especially after one wearing when they will start to fray. And they're made out of plastic.
It seems like with all the natural inspiration in this world, a company could design its own shoe?