In the "American system", in most major sports,
individual players (and coaches, effectively) are relegated and promoted between the big league and smaller developmental leagues all the time. I don't love the American system but a failure to ensure that our top talent plays in the top leagues is not one of its deficiencies.
In terms of meritocracy, I'd say it works at least as well as the European system.
As an American I would admit a preference for the promotion/relegation model but when I look at how a league like the English Premier League functions I don't find much to be jealous of. It's basically just a contest to see who has the most money... the teams with huge amounts of cash win nearly every year. Greed wins. And the fat paychecks for Premier league teams assure that the rich stay rich. It's hilarious to think of Man U being relegated because it could happen but c'mon, it's not.
The main difference is that Euro football leagues give the illusion of adhering to the sport's amateur roots. Theoretically your local town's team could play its way up to the Bundesliga or the EPL and win it all. However... that is basically an illusion. Occasionally a team like Cardiff City fights its way up to the Premier League, takes a beating, and sinks back down to the Championship League. They never really have a chance. Once per century you get a Leicester-style miracle, which is extremely cool but it's the exception that proves the rule.
Basically both systems are nearly equally ugly but the American one is more honest in most regards.
However I will agree that the proposed Super League is a terrible idea. The Champions League is special because it pits the best against the best every single year. That will be much less true for the Super League.