Yes, perhaps that's why he said it. Manchester United, who nearly went down in the Europa League last year, and Tottenham, who were relegated, met in the Europa League final. Despite playing very well, Manchester United lost, and Tottenham won the final. Tottenham will be in the Champions League this year. Because the Premier League's difficulty level is vastly different from that of the Europa League, many English teams were seen as the natural favorites. Similarly, English teams are the favorites in the Conference League.
Apart from the competitive nature of the premier league, another reason English teams are often considered favorite is because of the quality of their team and their coaches are mostly experienced and determined, so it makes it enough to consider them favourite, moreover these teams invest so much in their depth and they are mostly targeting the champions league so playing in the europa usually do not link really challenging to them because it looks like they face average teams often from other leagues.