Napoli won the last series after many years but year they are far behind so i also agree with you that they can't do better because they are behind in huge points which they won't be able to cover. Juventus are very good team this time last 3 years ago 9 consecutive champions in Serie A. And since then I am a big fan of them. Juventus is in a very good position this year too and can be expected to win the trophy. But Inter will be a big rival for Juventus because Inter is 12 points ahead of Juventus still now
Overall, Napoli's performance this season has been quite poor with all the problems they are facing and in my opinion, the mistake made by Napoli's team management in changing coaches has meant that the team's performance has not improved, on the contrary.
Now Napoli are quite far behind, so I don't think they will be able to improve significantly to catch up and compete to finish in the European zone.
While Juventus has indeed had quite improved performance this season, unfortunately Inter Milan has also developed much stronger this season, meaning there are no Serie A teams that are currently competing fiercely or are able to put pressure on Inter Milan at the top of the standings in the race for the Serie A title this season.