*THE two most iconic superheroes
I still don't see it making Avengers level money. JL probably will but the audience just isn't established enough for DC to just BTFO of marvel.
I'm not saying it's going to BTFO AoU (you'd have to be based Jim to pull that off). It will however, be pretty fucking close. These are of course people's childhood heroes that will be appearing together on the big screen for the first time, not a green rage monster or the star spangled HELP ME TONY.