It totally is WB's fault. Look at the reach of WB, TV, radio, magazines, it's a big company that can be pushing the movie on several fronts. One would think this close to a new Superman movie all the WB TV channels would be tripping over themselves to cram any Superman related content they have on air.
Look at Iron Man, there's a new poster, bit of film, tid bit every couple of days. Makes me jealous as a lifelong DC fan to see them not being as aggressive as Marvel. You know there are radio commercials on sports radio stations for Marvel? I heard commercials for Age Of Ultron, Superior Spider Man, and a bunch of other events on the radio.
No hate for Marvel, in fact I love Iron Man. I just see their publicity machine rolling and think how a huge entity like WB doesnt have Superman out there more.