City and Chelsea were the last to join and have been reported as the most reluctant.Tweet
— Twitter API (@user) date
Things might start getting a bit more interesting if there's any truth in this
Seems this has largely been pushed by the Americans (United, Liverpool, Arsenal) together with Perez and Agnelli. The others just came along for fear of missing out.
If Chelsea & City pull out, I wonder if Barca, Spurs, Atletico, Inter and AC Milan might follow.