In the context of European sports, one of the defining characteristics that generally makes it stand out from American sports is the "open" nature of competition. This is more simply known as promotion and relegation. European football, rugby, cricket, and other fields sports punish weaker teams at the end of each season and force them to play in lower tiers of competition.
This is not true of sport in much of the United States. The systems are closed. The NFL, MBL, NBA and even domestic soccer's MLS, all have no relegation mechanism. The opposite occurs in fact. The weakest teams get earlier draft picks, meaning that US sports are typically more balanced than the laissez faire European leagues. The US leagues are generally controlled and managed by the owners of the franchises. In Europe, the clubs are almost always answerable to a different and 'independent' body that administers the competitions they compete in.
In 1888 the Football League was founded. It was in essence a break-away but up to that point fixtures were generally arbitrary. The twelve founding members competed until January 1889. The 4 bottom teams were not relegated but the concept was there - all 4 successfully sought to be re-elected to the league. Therefore, the idea of relegation has been within the Football League - the first football league anywhere in the world - since it's inception.
In 1992 another break-away league started in England - The Premier League. This was an innovation inspired by sports across the Atlantic. There was opposition at the time to the creation of the Premier League. The movement of all games to subscription television was one of the most contentious issues. 30 years on this decision has revolutionised the game. It has turned small English cities and towns into globally recognised places. Stoke, Burnley, Norwich, Bournemouth, Brighton. The list goes on.
The announcement of the next break-away league involving English clubs - the European Super League - is nothing new. There are however a number of key difference between this and both 1888 and 1992.
The first is the competition structure and removal of relegation. Such a move would be an Americanisation of European football and a major departure from the accepted norm.
The second is the step outside the national boundary. While European competition has existed since the 1950s, qualification to this was through the domestic leagues. The new Super League would eliminate the need for this.
The third strikes at the monopsony power of UEFA. While a monopoly is a single seller of a product (something many of us are familiar with) monopsony is a single buyer. As a result the monopsony essentially controls the market as it is the sole purchaser of the goods or services that potential sellers wish to bring to market. This market power can be wielded in order to control the market.
While the major US sports such as NFL, MBL and NBA are better examples of monopsony power, UEFA holds this in a European context. Should one wish to play professional football or operate a football club, UEFA is the sole buyer of this service. It therefore holds monopsony power over the market for European football.
A European Super League would end this, and create a new dynamic in the market. The clubs would be self-governed within this new league and would make the structure resemble something much closer to the American model rather than the European system.
UEFA are not lying down. A ban on playing in all UEFA and FIFA competitions (e.g. the FIFA World Cup) is now the penalty for playing in the new Super League.
This has a long way to run. Supporters are notoriously conservative when it comes to changing aspects of the game that have deep historical roots. Even largely superficial changes to colours or names have been vigorously rejected by supporters. Moving location - another regular happening in the US - is met with fierce opposition in Europe. Completely upending between 60 and 130 years of competition structure (depending on where you want to draw the line) will be far from straightforward, if even possible at all.