There were 70 men in the peloton that needed to chase down the 30 man breakaway. Of those 70 only 4 men put the work in at the front, Stannard (GB), Wiggins (GB), Miller (GB) and Froome (GB). That is the simple reason why it became impossible for a sprinter to win.
Like Cavendish said most teams are happy to not win as long as Great Britain don't win. It's shit but that is due to the strength of our team overall and having the world's best sprinter.