I showed the video of ballets C de la B's piece, Ashes, to a friend and he made me laugh saying: 'Why do people always look like tramps in contemporary dance?'
Hummm... yeah... it's true that they often look like they are wearing their own rehearsal clothes, or are in their underwear...
Budget issues, most probably?
But it's not always like that, of course. See Guillem/Maliphant/Lepage's Eonnagata and its Alexander MacQueen costumes. I also had a look around and saw this video for Inbal Pinot & Avshallom Pollak Company, from Israel (part of Dance Umbrella 2009). Great coiffures!