Milan is just a bad team in the first place, they have Gimenez, Felix and Walker, their performance aren't that bad actually, they can still perform. Bologna's squad is a combination of young players who not able to reach senior team, second tier players and old players who no longer playing in senior team, yet Milan still lose.

Better to sack the manager instead, maybe Italian teams good when they get managed by Italian managers too. Inter, Atalanta, Napoli, and Juventus are managed by Italian managers. Milan was better when Stefano Pioli was the manager.