As a Napoli fan, i think it’s going to be a fierce battle for the Scudetto this season. Napoli has brought in some really quality players, especially KDB, who, from what i’ve seen in the preseason matches, is not exactly in top form at the moment. As for Milan, i think they will take things seriously and start playing seriously. With Luka Modric, anything is possible 
I don't know why older players like Luka Modric and KDB are still accepted by Serie A teams right now, but that's not a big deal as long as they still believe in their abilities. However, next season, I'd like to see how things play out for teams like Napoli, Milan, Inter, and Roma, because that fierce competition will always exist when all teams are of equal strength and their commitment to the Scudetto must not wane. But for next season, I still consider Inter Milan a team that will overwhelm its rivals in their quest for the Scudetto.