Need three matches later for AC Milan possibility reaching Napoli points right now, behind left 8 points and Milan position currently as second place I don't think have easy opportunity for getting back 1st position standing. AC Milan have inconsistency performance in Serie A last three matches, defeated by Torino 2-1 and won from Spezia before losing full points after draw with Cremonese.
Still not close yet with Milan opportunity back to top standing position, but need win all matches left and hope Napoli can defeated at next several matches and loss their points. However Napoli have consistency performance with unbeaten record than AC Milan can't in the winning track.
There is still a chance to catch Napoli's points, although it can be said that it is difficult to catch eight points with the leaders, at least in the last three matches they have been on a good track, winning against Fiorentina, Spezia and drawing against Cremonese. While Napoli have an eight-point lead to maintain the standings, they are required to win or at least draw their next few games.
Looking at the league, Juventus seems like they have a better momentum to be fair, I know that not many people will agree with me here but with players coming back from injury, they may end up playing much better than Milan. In that case we may end up seeing Juventus take the second position first, then they could take the first position from Napoli, only if Napoli starts to lose a lot of games of course.
They still have zero losses, and it is obvious that they are going to eventually have at least one, probably 2-3 by the end of the season at least, and that means if they have only that much, it's fine but if they end up losing 5 games or so from here on out, they may lose that points advantage they have.
While Napoli were in quite convincing condition when the match started, they had a point advantage in maintaining the standings, however, this opportunity must really be used perfectly, because if you suffer one defeat, it will have an impact on the next game.
Juventus have more time and concentration to prepare for Serie A, while Napoli and AC Milan are still playing in the Champions League, this will also affect the condition of the players in preparation for the Scudetto (my assumption). That's why what you said is more relevant, given the chances of the three clubs.
AC Milan's current position is indeed in a very possible place to catch Napoli at the top of the Standings, but you also have to see how Napoli's consistency will be after the world cup later. Because if Napoli are still quite consistent in every game for the rest of this season, it will be difficult for other teams to catch up with them at the top of the standings, including AC Milan itself. This is not only due to the opportunities for other teams besides Napoli, but also due to the gap in points that Napoli already has at the moment.
All possibilities still have a chance to happen, even though it seems that Napoli has the advantage in chasing the Scudetto this season. But all of that will get easier, the three Napoli are able to play consistently in the second half of the season, because if they get a draw or lose, this opens up opportunities for challengers to catch up on the points they currently have.