There is nearly no possible way for Juventus to be second this season. They are at 59 points and Napoli is at 68 points, that means 9 points difference both teams and there are only six games left. That means, Napoli needs to lose 9 points, as in 3 games of the last six games, does that make sense to you?
It doesn't require losing 3 games, but a few draws and one loss would be enough to shift Napoli position. And Juventus need 4 win streak to catch the point difference. But as you said, that realistically isn't going to happen.
We can see Napoli suffering a defeat or a draw, but expecting Juventus to get win streak is something that very unlikely. Meanwhile, Juventus attack line performance is not as strong as a few years ago and this time Juventus only relies on the defense line.
So in this statement I support your opinion that Juventus will not be able to catch Napoli.