Napoli have fallen far behind so it will probably not be possible for them to get back into a good position again this time. The way Inter are playing makes it much easier for them to become champions. Inter are ahead of the other teams on points, so it will be very challenging for the other teams to overtake them. Napoli didn't focus on their performance early on which is why they are in the situation they are now. So I can't consider Napoli as likely to do anything good ever
Napoli have started to bounce back to winnings gradually. Things can be a little bit rough for them but they can survived in the long run. Napoli president, Aurelio De Laurentiis is incharge and he controls every activity that governs the club currently. He's the main reason Napoli remains tall and strong this very day, he ensure everything works out so smoothly and improving in all rounds of the game. Appointing Walter Mazzarri as headcoach was one of the good decisions made because he's present to turn the club around for better development.
I don't think that replacing the coach is a guarantee that they can change their performance and now it has been proven that Napoli are not completely consistent and in fact I think that at the moment they are not really considered to be competing at the top in the race for the Scudetto.
Mazzarri has only played a few matches and it has not been proven that he is better than Rudy Garcia so in this case we cannot conclude anything yet.
However, personally I am a little doubtful that Napoli this season can improve or be like last season.