Of course, like usually, you can find a reason for almost everyone in the group not to ride: Roglic didn't have the best day, Yates is not a good sprinter, Alaphilippe has Masnada ahead, Gaudu says: but Jumbo still has a helper, Bardet says: but Ala is going to outsprint me, Valverde says: I'm too old for this ** (or whatever his reason is)...
But what they forget is that there is a reason to ride full, and that is that they want to win and if they don't ride they have a 0% chance to win (okay, maybe 0,1 because Pogacar and Masnada might fall off their bikes after crashing into a dog who run on the street) while when they ride a bit more than their rival they at least have a chance of, I don't know, 15% or so.