I see impossible to see Napoli being champion of the SerieA back to back, they never do something like that plus Inter needs to win something asap after losing it all in the end of the last season.
This plus this Napoli seems to be the best one and when this kind of teams are in that particular position they start to fall.
In fact, it's more likely to be difficult for Napoli to win again next season, but that doesn't mean it's impossible, as it can sometimes happen unexpectedly. I also really didn't expect Napoli to win Serie A last season, even though before Napoli won, Inter Milan held the top spot for quite some time until they made a mistake and were overtaken by Napoli. However, next season, Inter Milan still has the potential to reassert themselves as title contenders from start to finish, as long as they don't make any fatal mistakes.