Honestly it's quite remarkable that The Avengers got made at all. Warner Brothers has the rights to almost the entire DC Catalog, while Marvel's catalog is spread out all over.

Marvel Studios has the rights to The Incredible Hulk (which they got back from Universal), Iron Man, Thor, and Captain America.
Columbia has Ghost Rider (They can keep it!) and Spider-Man.
20th Century Fox has X-Men, Fantastic Four, Daredevil/Elektra, and Deadpool (which must fall under The X-Men).
New Line had the rights to Blade, I assume they still do.


It'd almost seem like a JLA would be a shoe-in after that clusterfuck. However Marvel was smart about one thing; they made their own production company with an eye on an Avengers film. DC just sold the rights off as single properties with no plans of ever trying to do a team-up type of film. I'm not sure how JLA would go over now that The Avengers is out as it'd be pretty obvious DC/Warner Bros. would be trying to cash in on the success of the Avengers.