Leicester City was an amazing story, but I think it was pretty flukey, relying on uncovering two of the biggest diamonds in the rough in recent times (Mahrez and Kante), who then got transferred to Man City and Chelsea. Any smaller club that gets momentum can be kneecapped before they really have a chance to play together and win trophies because of the transfer system. Southhampton made it as high as 6th before losing Mane and Van Dijk to Liverpool. Ferguson's later teams perfected that art, poaching younger guys like Wayne Rooney, Ashley Young, and Antonio Valencia from smaller clubs who gladly took the transfer fees. They also showed the hierarchy within the hierarchy poaching Berbatov, Carrick, and Van Persie from 'big' teams like Arsenal and Spurs. Man City has basically replaced them at the top in both the table and transfer strategy, picking up young talent like Stones, Sterling, Walker. I think Arsenal wanted the Superleague because they realize that they have been a small club for a while, so want to cash in on their history before they become Everton.
Of course, Bayern has also done this with Lewandowski, Gnabry, Sule... etc. Look at the young talent that Dortmund has assembled. In the American franchise system, they would probably win a lot of titles with a core of Haaland, Sancho, Bellingham. Instead, they get raided as soon as they start to realize their potential. The one caveat to the whole comparison is that the transfer system is probably better for the players in terms of compensation. The looming threat of the big clubs pressures everyone to pay young superstars a more fair value. So there are trade-offs.