Where is that 'no motivation to succeed' myth is coming from?
I am not following American sports, but if I'm pretty sure that there were more different winners in the NFL/NBA/NHL/MLB in the past 20 years than there were CL winners. And I know that that the Superbowl for example is the pinnacle of a player's career. When the Cubs won the World Series in 2016, Chicago was like Manchester in the days after completing the treble. When the Blackhawks win the Stanley there is an informal holiday for a couple of days when nobody goes to work and there are huge parades.
So I am genuinely asking, where are those myths about American sports come from? I start to feel that posters just repeat what others say because it's cool to make fun of American sports.
It's not a myth, but it is focused on the money distribution along the teams, not on the players on the field. And in a way the American system is not bad - because all teams get mostly the same amount of money, no matter how well they play, they only need success to make the dreams of the players come true, their paycheck do not (much) depend on their success. So in a way it allows the sport itself to be played in the most open way, as money is not a factor to differentiate the teams. Crazy that this is kind of a communist approach, and works in the most capitalist country of the world.
In contrast in the European system more success means more money - and more money makes it easier to get more success. This system increases the chances of the established big clubs to win (as we see in the national leagues as well as in the CL as you mentioned), but it also forces them to be successful, and if they fail they can quickly be in big trouble. Just look at Schalke - were regular CL starters, did inflate their budget a lot based on that, failed to get to the CL and to get the money, and where despite their big income still not able to make any moves on the transfer market on the necessary level, and now they are relegated.
Such a collapse is not possible in the American system, and the clubs behind the super league tried to get this guarantee that their income can't collapse by establishing that they cannot be relegated from the super league - but this also means that there is no chance for teams not in it from the beginning to join their ranks (that idea with 5 qualifiers was just a stupid distraction I think, did not change the big picture of the super league proposal).