When a film becomes a true phenomenon of that level, it almost always becomes impossible the replicate for the sequel. In large part because the demand is driven in part for some specific reason that can't be replicated (ex. first time iconic character is on screen, first massive team up between popular characters, first film in popular franchise in years/decades, some sort of new original gimmick, is released on some major anniversary for the franchise such as the 50th, etc.).
I don't expect the next Jurassic Park, Star Wars, or Fast and Furious sequels to be able to match their predecessors either because of how inflated those grosses were.
And this is a problem going forward for Justice League. BvS did have an advantage in that it was the first time Batman and Superman (and Wonder Woman) were on-screen together. That gets the novelty crowd. There is nothing Justice League can do to match that level of excitement, unless Ben Affleck dies and it ends up being his final film or something of that magnitude. That BvS had this advantage and still did so relatively poorly speaks volumes about how poorly received the film was.
