I don't think much of that is realistic to be honest. For example, what can the UEFA do right now, starting today? Ban all players from those 12 clubs for the Euros this summer? There will be an actual chance riots would break out in countries that are heavily affected by this. Players are also under contract so it's not like that can magically switch clubs in the coming weeks in order to comply with what UEFA wants.
Same for the Champions League this season, are UEFA just going to ban Real, City and Chelsea and cancel this years edition right now? They would have to pay a shiteload of sponsorship and tv money back, and then what? They will basically force the clubs to start their Super League for sure after such a decision.
Similar for the FIFA, they want to ban players from playing in Qatar next year? There's already a huge negative public opinion towards that tournament, and a negative public opinion towards FIFA's blatant corruption. Excluding some of the biggest players in the world would only add to that, and most importantly cost them a shiteload of money due to sponsors losing interest or wanting to renegotiate the current contracts.
Most big name players are under contract at their current club as well, why would those clubs want to sell them? Another question would be, what other club would they join? All because the corrupt FIFA and UEFA don't want their clubs starting their own European leagues, someone like Messi should leave Barcelona and join Olympique Lyon?
They have some options though, like you say try to create friction between the new ESL clubs. But more logically it seems like the big clubs have a small advantage in this matter, and UEFA will just give them want they want in the end.
Actually, I'm sure players have all the right to terminate their contract if the clubs see this through. To be honest, I believe it's quite simple. The World Cup and the UEFA are tournaments organized by these associations for members of these associations. With their venture the clubs have deliberately violated the terms they agreed to so both federations have every right to expel them. It's completely self-inflicted and only consequential. It's not vengeance motivated but just the rules. They can't play if they are no members of the association. Period.
Same goes for the UCL. You can't just continue with the semis. They have violated the rules every single club has to stick with. If I were them, I'd throw City, Chelsea and Real out and go with the last team that was beaten by the semi finalist and still is in the association. So it would probably go Dortmund - PSG and Atalanta - Leipzig. Oh and by the way, in their stead I'd also check if I can sue those clubs for compensation in order to pay any compensations those associations have to pay their business partners due to them violating the regulations they agreed on. Though I admit, you could finish this tournament since the clubs are only intending to start the competition next season, not this one.
And yes, that's exactly what Messi should do. Probably PSG instead of Lyon though. In the end the FIFA is an association. It might be worldwide and more less including every football club out there but it still is an association and if you want to play a tournament of them, better play for a club that is a member of said association.
Do any of that and they may as well call it a day. Football is made by the players and using them to assert their own power when their own greed is being complained about is a bit reductive. They've already lost the support of the clubs, but due to local media interests and fears, and the terrible ESL proposals, have come out looking like victims. Enforce those moves and the moment players start to complain, clubs start advertising UEFA corruption as the reason for their break away and the local media start reviewing that, FIFA and UEFA are done. The players are the ones with the fans, if they feel aggrieved, there's no way back. Personally, I feel UEFA were arrogant to even try to enforce the proposed 2024 format without the support of these teams. They could have negotiated during the summer instead of trying to enforce those changes.
UEFA and FIFA might be corrupt but in this case, they are just an executive body, seeing through the consequences that are set in the rules which are binding for all clubs.
It certainly will be interesting to see which players renounce to get 4 times their current salary to play the WC instead.
Yes, this will be interesting. Anyway, I'll be even more interested in whether the calculations of the ESL are on point or not. Those amounts of revenue seem ridiculously high, even for such a league. I mean, if people become bored by the league because the big fixtures lose their magic through routine, it might bite them in the ass. They'll be fighting boredom on the one side and open hostility by large chunks of their former fans on the other side.
This could in fact become really, really ugly depending on how the ultras react to this.