The champions league and the top 4 of the premier league will always be bigger than the Europa league. When big teams are in the competition, they go on to win. Chelsea has been in the competition twice and they won it. Manchester United would have allowed Chelsea play the competition and it would have been won not what they're doing disgracing the premier league over there but there's a good news as the new manager coming is looking like someone that knows what he's doing. He just beat Manchester city yesterday but he'll be coming to join a different squad of players and I hope he can work with them, the same way he was working with the sporting players to win.
I don't think so, because every time big teams are in the Europa League, they have a hard time winning the title. I don't know if it's because they're not serious about winning or if there's something else, but what's clear is that in several seasons no big names (like the teams you mentioned) have been able to win the Europa League title, even though they're in this competition.
Now for the competition itself, I think I also agree with what was said. This season is the first season we won't see a team that was relegated from the Champions League here. Usually we'll see 8 teams fighting for a ticket to the last 16, (8 teams from 3rd place in the Champions League), this season we won't see that.
Basically bigger teams are teams that should have been in UCL but failed to get there, so they are forced to be here instead, and players there do not care about it as much. Like last year with Liverpool, they were basically leading the league before they got out of Europa, if you go back and check the dates, when they lost to Atalanta, they were leading premier league and then after the loss everything fell a part for them and they started to be terrible and lost the league as well.
The main reason why they lost to Atalanta wasn't because they were bad, but because they didn't see Atalanta as a good opponent and they just played not as well as they could. This means bigger teams have problems of underestimating their opponents quite frequently here. Even in UCL, there are many times we saw smaller teams win, and that is because bigger teams just underestimate their opponents. These are tough competitions, nobody should be underestimated at all.