I think by now it's clear that he won't meet the expectation of winning Serie A that most of us understood as the metric for success. We are also far from challenging for the league title.
So now the expectation has dropped to top 4 finish and even that seems uncertain. Folks are making comparisons to Klopp taking a few years to build the winning team. For starters, Klopp inherited a team that hasnt touched a trophy in a decade, and was competing against multiple teams that were spending crazy money every year. He didn't inherit the league's richest team, and his competitors didn't have to do a sell-off of their coach and key players.
But more importantly, Klopp from his first season imposed an identity and specific game plan and built around that. He has a philosophy, a style of play that was visible. You could see the players getting used to it more and more, there was progress on the pitch, players improved and then he added players to the team that fit this style of play.
We see none of that with Allegri thus far. This season is more like Ole's season this year, and less like Klopp or Pep's first season. We still don't know what his idea is football is. We are not seeing any emerging patterns of play. Changing players and formations over and over. The only constant is chaos. Players that just had a beastly Euro have turned to shit. Players that had a good season under Pirlo (Ronaldo aside) have regressed. Morata, Chiesa, Cuadrado. Mckennie, Kulusevsk, De Ligt.. heck even Rabiot is worse this year than he was last season.
The Klopp comparison is invalid. He wouldnt have kept his job if his team looked even more clueless, playing uglier football with worse results than his predecessor at the end of his first season. We are only ~halfway through the season, Allegri still has time to at least show some signs of progress. But the clock is ticking.