5 years on the highest level is like a lifetime. besides atleti, not a single top club is being coached by the same coach for 5 years. we had ONE single weaker season under allegri, and that's only valid for the cup competitions: atalanta and ajax have weaker squads, smaller budgets. we never lost to underdogs in any club competition for 4 fucking years. for 4 years in a row, we always beat lower rated italian sides in the cup (and that never happened under legendary coaches like lippi or trap), and in the cl, we always lost to wealthier, higher rated teams.
sarri never coached any team for 5 years. sarri lost several times to underdogs and weaker teams in his three years at napoli. sarri never was the synonyme of consistency with any of his clubs. i'd be fucking happy with sarri if he could "fail" and "stagnate" like allegri could.