It is true that Napoli has changed their poor performance, and they were lucky enough to win the Scudetto this season, but I don't see Napoli as the favorite to win the Scudetto next season because if not for Inter Milan's busy schedule in the UEFA Champions League competition, Napoli wouldn't have won the Scudetto this season. In my opinion, Inter Milan is the favorite to win next season's Scudetto because they will want to make up for their mess next season.
First of all, Inter without Inzaghi can become a different team, the same goes for Milan with Alegre, and maybe even Fiorentina with Pioli (although I'm not so sure about that). After Juventus lost its dominance in Serie A, this champion has become very changeable, the leaders are constantly changing, and it's difficult to predict anything, by the way, Napoli have never been famous for great stability over the seasons, and they will have to play in the Champions League, which can affect their results in Serie A.