it's all about cycles at napoli. their previous one is ending, and not a single coach could probably stop it, not even sarri in case he rejoined them. hamsik left, mertens slowed down, albiol left, callejon won't renew his contract, koulibaly probably wants to leave, etc. they fell apart as a team. look at spurs, they have similar issues. they still have quality, but that's not enough to produce the same results anymore.
let's hope it's not the case with juve. numbers and our form are worrying, but the quality and the depth is there. not sure about gameplan, organization and motivation.