Will you guys calm for a second! There could be multiple reasons for Allegri to not start Dybala every game.
Stop the 'omg he's leaving' talk already! He's still adapting to the city, teammates, tactics etc.
Allegri has to set an example of how you get to play, and when you do. Dybala knew he wouldn't come here as a starter, his former coach at Palermo, Iachini, reminded the media and fans with this as well. It will take time. The team is before any player, and the reasoning as well. Dybala is a second striker, and when we play 433, there's no second strikers in that formation. It requires a LW, RW and CF. Cuadrado is a RW, Zaza a CF and when it comes to LW, we have Pereyra who's first in the pecking order here since dropping down at the pickings of AM and CM(b2b) positions.
To blame Allegri for not playing Dybala from the start against that Frocc.. Fro.. Focaccia whatever isn't just. Only if we played a 4312 or 352, I would argue Dybala is a no brainer from the start. But we played a 433, and other players need to play as well. To be honest, Cuadrado and Pereyra were among the best players in this match, and Zaza had to get some playing time at some point as well. Why not trust the guy in a match we were 'guaranteed' to win?
Some people have played too much manager or Fifa to misunderstand how coaching work in reality.