We have tons of depth for rotation across our entire defensive line. 5 very good CBs (Bonucci, Chiello, Barza, Rugani, Benatia), and 4 very good fullbacks (Sandro, Licht, Alves, Asa). We have good midfield depth now that we play a midfield 2 (Pjanic, Khedira, Marchisio, Rincon, Lemina, Stu)...
Those are the positions that expend more energy while shutting up shop.
However, our attacking line has no depth at all. We literally have 4 attackers, while our primary formation right now requires 4 attackers. Pressing the other team, and pinning them back like Napoli, Roma, and others would require much more energy expended from our attackers... whereas shutting up shop as soon as we get a lead, allows Higgy and Dybala to really do nothing, aside from half-hearted defensive effort (which is exactly what we see from those 2).
I am sure there are other contributing factors, but I think this is a part of it, especially since when we started with this formation in January and the first 2/3 of February we were attacking far more and taking the game to other teams even in the league. It's only really vanished through the month of March, where we are going into a defensive shell and energy conservation mode as soon as we get a lead, and I'd assume that has something to do with a lack of depth in attack.
