The whole competition narrative is false imo. The best years for Juventus in the champions league were 2017 and 2015. In 2015, they had absolutely no competition. In 2017, it was probably one of the best years for serie a recently, but juventus were still comfortable winners (more comfortable than the final league table suggests). Last year, when they were under intense pressure, they went out at the quarters, the same spot that they did this year under none at all. The problem lies elsewhere in that club. Bayern is a good example as well: they were run away league winners in 2013 (although dortmund were strong that year), 2014, 2015, 2017 and 2018, with the league slightly closer in 2016 and close in 2019. They've gone winners in 2013, semis in 2014, 2015, 2016, 2018; quarters in 2017 and ro16 this year. There is no clear correlation between stronger competition for the win and better european performances imo. I agree that overall league quality helps every team in that league, but the issue isn't not being challenged, but just being low on quality. The prem was competitive between 2013 and 2017, but low on quality which showed in europe.