Because if I want to pay $140 for a dress, I'll go to J. Crew, or Anthropologie... where they are beautifully made, fit beautifully, and last years. If I want uber trendy pieces that I'm not even sure I'll still be able to wear next year, I'll go to H&M and pay about half of what TopShop is charging.
The quality of the pieces didn't even seem like it was really that great for the price, which you know to a recessionista like myself is a must, esp. if you're going to fork over more moolah for it.