It surprises me a bit that Jumbo didn't try more to work him over, but I think two factors were against Jumbo:
1. the headwind, making an attack hard and risky;
2. Roglic maybe not having good legs, so if Vingegaard would attack and Remco would follow, then Jumbo would actively have ruined their two-prong attacking chances in the coming stages. And Vingegaard also said he wasn't on his best.
Given Remco's sprint, he could have taken more time by going even earlier, but as there was headwind, the further = the more risky to not get any daylight and having 10 riders overtaking you in the last stretch.