Cav doesn't need a lead-out train to win bunchies, look at yesterday's race.
That is of course true, because he is the fastest sprinter on the planet. But if you look at the aerial view of the last k yesterday, precisely because his lead-out train didn't work, he could have so easily been boxed in on the right, and Matt Goss would have been champion.
Having a great train is not necessary to win sprints, but evidence suggests was necessary for Cav to win the tdF Green - despite Highroad's single-minded attempts in previous years and his form this year, it was only clinched on Champs-Elysees.
In fact I think Renshaw or Goss could possibly have won it yesterday if Renshaw wasn't sidelined by the Aussies, but that is another story.