What? I would argue the other way round: The 777 wing is so inefficient, it doesn't need any winglets
Face the facts: 777 is a great success, just because you compare it with a 747-100 or 200. If you could compare it with a 330-"600", it would show you the way it goes. That's why most Asian airlines use 330 *and* 777: the former for short haul, the later for longer flights.
Dani