That can not be denied.
What people object at though, is the fact that Diego was supposed to be the guy who'll make things happen, but he's not doing that. Something like Kaka in 2007/08 Milan. That team played just as bad as this year's Juve. But from time to time Kaka would have taken the ball in his legs and do something useful. Score, assist, win a penalty. We all know that Diego can't win us every match when the others are shit. And we don't expect him to. He can't win us every second, every third match either. But on some ~25 matches this year we played the way we played today and on none of those matches Diego saved us.
Take Del Piero until last year. Even when nothing worked he was able from time to time to win us a match with a single move. And Ale was 34.
We knew when we bought Diego that the team has to spin around him. No-one was doubting Diego's talent but I remember Vlatko doubting that Diego posses enough quality for the team to spin around him and that if the team is set that way, when Diego won't play well the team won't play either.
So what can we say now?
Is Diego good enough to be your team's main player? No, he's far away from Messi, Ronaldo, Ronaldinho, Kaka, Rooney etc.