More precisely, there is half a season left for all the matches that all teams in Serie A will play and that is enough to change the position of each team in the standings. Indeed, Napoli is not safe yet, given the competition from several teams Ac Milan, Juventus and Lazio are still wide open for the Scudetto hunt this season. So don't be complacent in advance for Napoli even though their average difference is 10 points.
It is clear that Napoli are not safe even though they are 8 points ahead and the competition still has 20+ matches left
But if they are able to hold undefeated record then their potential to win the tittle is bigger and the team that will be their main competitor is Juventus, I see Juventus having improved performance.
Anyway, Napoli for me is safe enough at the top of the Serie A standings this season because I believe it's impossible for Napoli to continue to lose. Even though anything can still happen, a team that can be consistent until the first half of the season, at least they will have the ability to maintain good average results in each match.
At least that is one of the reasons I have, because I believe other competing teams will certainly not be able to consistently win, because to maintain victory in every match is a difficult job.
Even the strongest teams in different leagues, at least they will also experience defeats as well as draws.
With such a comparison, I believe that the ratio of wins and losses for Napoli and the teams under it can never be completely consistent. Because they also have a busy schedule and also changes in the line-up which will certainly occur after the transfer market. Therefore, to maintain victory throughout the season is something that is very rare.