Lol Marotta bought him the best 2 players in Serie A, the best right back in the world, a very strong CB and a few youngsters in exchange for losing Pogba (and morata). He has more than a good enough squad to play much better. Buffon said it clearly.
This is more on Allegri being unable to create a coherent game plane with all the talents at his disposal than with Marotta not giving him a good squad. This is a great squad on paper. Get them to play like a team.
I agree that he has a good enough squad to play better.
But let's be honest, two seasons in a row he has lost key players in his squad (Tevez, Pogba, Vidal, Pirlo, Morata). Two seasons in a row he has had to rebuild and gel a team. He did very well last season although who knows what would have happened if Cuadrado didn't score that last minute winner vs Torino.
We have replaced Tevez and Morata well and Pirlo had declined, but our midfield is nowhere near what it was. This is an issue when your squad is built around its midfield.
I think Allegri has made a lot of mistakes this season and should take a lot of the blame, but Marotta has made life a lot more difficult for him.
I also don't agree with Dani Alves being the best RB in the world, he has been far from convincing.