A thought:
At some point in the race, I believe Sagan had (according to GPS) ~55 seconds on G1 and ~1:15 on G2. G2 contained 3 Quick Step riders (Stybar, Gilbert, Lampaert) but as far as I recall they were doing no work, I think it was Vandenbergh who was working in this group. Shouldn't Quick Step have started working at this point? I understand that they wouldn't want to bring that many riders back to the Terpstra group, but with the Terpstra group failing to make up time on Sagan, you'd think it would have been the better choice. With 4 riders in a ~30 rider group and Terpstra probably the strongest besides Sagan, they would have had a great chance to win, as long as they would have caught Sagan.