They looked to be in decadence last season, too. And then the only difference between us and them was a ref, and we annihilated the rest of the competition in CL
Truth is they were the best team in the world when they lost to Atletico in 2016, and they were the best team we played last season.
Age might be an issue with Robben and Ribery, sure, but people were saying this last season and then Robben turned us inside out at the bernabeu. They remain a juggernaut until proven otherwise, and that's in Spring. First half of the season is meaningless, their superiority over the league is such that they don't need to be great to dominate from the off.