What's the deal with designer clothes?

I see fashion shows once in a while on TV and I always wonder do people actually buy that stuff besides celebrities? I could probably get away with wearing some of the outfits on the street but the others just look too outrageous, for example, the one on the left (click on image to enlarge). No disrespect to the designers—I'm not hating or anything. I understand they want to be different and push themselves to get noticed in the industry, but I was always curious if people buy these outfits other than for display? And if they do, is it really worth the money?







I'd rather buy this if I could afford it:
(A dress from Donna Karan's Spring 08 runway collection)





Enough about apparel, let's talk about shoes. I've been looking for a pair of leather boots that are fashionable, comfortable and versatile, like the Dolce Vita Haute Ecole Boots from Urban Outfitters (left) OR the Leather Foldover Boots, also from UO (right):


      


I tried on three similar boots when I shopped in the city today, but they just weren't the ones! It's like my feet have a mind of its own. I know when I'm trying on the perfect shoes :) I already have a pair of boots, but they're the UGG imitation suede boots which are bad for snow and rain. They're very cozy but only good for those very cold/windy days. I guess I'll take a trip to UO soon to check out these puppies. Wish me luck!