Like I said, it's literally quite hard to judge given the things that were going on. A clearly very corrupt period in Italian football coincided with Ancelotti's biggest 'underachievements' in terms of league results. I've always found it a strange stick to beat him with.
As for Capello, Juve were stripped of their league titles under him. Which doesn't have to mean he didn't coach them well.
Same with Lippi. The Juve 1996 side that beat Ajax in the CL final were doped up to the max. They loved
their EPO. Doesn't mean Lippi didn't coach them well, doesn't mean they weren't a great team with fantastic players. It does mean they were disgusting pieces of shit, they were simply cheaters who should be stripped of their title.