I'm sure that Napoli lost this game on purpose. They are not in the best position in the Serie A standings and they need to keep playing in the Champions League. The Italian Cup is not important for them and they will not waste strength on it. The main thing for them is to improve their position in Serie A and try their luck in the Champions League.
Regardless of whether it was intentional or not, it was still quite disturbing to lose so badly even in a match that didn't really matter against a club that was weaker than them in every way, which was quite disappointing and a disgrace for a big club.
Indeed, for their reasons in this case it is quite understandable because the current situation they are still not very good in Serie A and prefer to look for better opportunities, namely the Champions League and Serie A rather than the Italian Cup but if this is deliberately losing with an embarrassing score like this I think something is not too wrong in the body of Napoli even though we know most of the players are young players who are given more opportunities to show their skills on the field.
I'm sure a lot of people have lost faith in Napoli this season, the way they were eliminated in the Coppa Italia cannot be accepted by common sense. How could the goal margin reach 4-0, that is very embarrassing and raises a lot of questions. Choosing to be eliminated in the Italian Cup is not a good idea, because who knows, that is the most realistic trophy that can be achieved this season.
Mazzarri is not a good successor in replacing Garcia, in fact I think Garcia quality is still better than him. This is what most people worry about, that changing coaches does not guarantee that everything will be better, Mazzarri proved this to be true by making Napoli lose one competition.
In Serie A, I think Napoli only has a chance to finish in the UCL zone, while talking about defending the Scudetto is over. I mean it is no longer possible to catch up on points from Inter, especially if Napoli management releases Osimhen in the January transfer window, that will be a setback for Napoli.