Michele Scarponi pointed out after the 2012 Giro that he and Basso had seen Hesjedal struggling at the back of the heads of state group in week 1, and done nothing about it as they figured he'd drop back as he was clinging on for grim death. Of course, Hesjedal tends to ride himself into form, and by the time they actually did get round to attacking him he was more than strong enough to respond. If Scarponi had told Niemiec, or Basso had told Szmyd and Caruso, to get on the front and absolutely drill it on those stages, Hesjedal is dropped and eliminated.
Jumbo didn't need to be sending Rogla out on a solo exploit or anything, but it was patently obvious Ineos' tempo was not them going all out to string out the bunch and drop people. While Roglič is in strong form it is absolutely in their interest to eliminate as many contenders as possible. Getting on the front and burning a few matches to reduce the bunch from 50 to 15 in size isn't glamorous, but it means far fewer people to watch in future stages. After all, it wasn't like Ineos were burning their guys running the tempo they did, because they were all still happily tapping away on the pedals all the way to the line, so you don't even have the excuse of making the rivals burn their domestiques. Enric Mas crashed and Sérgio Higuita was dropped at one point, you could test them out, and maybe just asking Kuss or Gesink to tap out at 90% for a couple of kilometres would have been sufficient to rid the bunch of some of the chaff and mean they have fewer people to keep an eye on later.
And if they did take the maillot jaune, they could always just ship it to a breakaway, you know? That used to happen all the time. Hell, one of the guys that did try and do something on the stage - Jesús Herrada - got to lead a Grand Tour in that exact same circumstance, to relieve some of Simon Yates' domestiques from péloton controlling duties.