Part of the problem is our opponents have no fear anymore. A couple years ago, they used to give us the ball and put all 11 in their own box. Since then it's been a steady growth of confidence game after game it seems.
I mean, we have literally substituted Pogba for Sturaro at LCM. Pogba was always hard to press, teams would back off of him because of his pace and strength. Vidal would always find a way to get in between the lines or even on their last man. Khedira is lucky to cross midfield.
It's just a loss of overall dynamism in midfield that gives the other team confidence to push on top of us.
But Allegri is not changing the setup. Perhaps if it was a wing based formation, you would see more hesitancy from the opposition. Cuadrado, Pjaca, Dybala on the outside are all more threatening to the opposition than protecting against the 3rd attacker, usually Sturaro or Khedira.
"Like ok, we are going to press and if they knock it up to Higuain or Dybala, and the 2nd ball falls in between the line, will Juve even have anyone there to take advantage? If they do, is it Khedira or Sturaro? Great then, who cares."