Everyone thinks the same about Napoli's good start in the league. But we have seen many similar scenarios before, those who start the league very well can experience huge performance losses in the second half of the league. It is a great achievement that Napoli have never lost a game so far, but they will also play very difficult matches in the coming weeks. I don't know how long this situation will continue, but I think they may start to lose points 
How not, 9 wins and 2 draw is an extraordinary achievement so far. so, it is very normal that many people are talking about it and make Napoli as a best candidate for champion this season. But, I agree with you, and yesterday I made a similar comment. since, Napoli are good at the beginning but often struggle in the second half of the season. This is an undeniable fact.