Warning: SPOILERS for Shazam!
It was a cosmic coincidence that DC's Shazam! movie would arrive just weeks after Captain Marvel. But as proof that the rivalry between the heroes of the same name is far from over, Shazam! ignores the existence of Carol Danvers altogether... to make a Captain America joke, instead.
Nobody can begrudge the makers of Shazam! for their choice, since Captain America remains the poster boy of Marvel's Avengers movie universe. Still, there aren't many chances for both Marvel and DC to throw eachother a wink--and two superheroes who became famous as "Captain Marvel" is as good an opportunity as they'll ever get. The best fans can hope for is Shazam's possible nod to Carol Danvers, before Billy Batson's superhero alter ego is officially named in tribute to Steve Rogers.
The movie is filled with Shazam! and Captain Marvel Easter Eggs, many of which play on the confusion surrounding the character's name. Billy doesn't actually receive or self-assign a superhero name in the film, which leaves his foster brother (and superhero sidekick) Freddy Freeman to come up with multiple versions. When Freddy uploads video after video of Billy's superhero training and day-saving, audiences can see how varied his YouTube video titles actually get. Referring to Billy's magical form as "Red Cyclone" and "Thundercrack," are believable placeholders... but one moniker stands apart: "ZAP-tain America."
The name makes sense since it's only given after the boys discover the true nature of Shazam's superpowers, directly connecting him to the "living lightning" that actually strikes him to pass on its magic. But the wordplay of "ZAP-tain America" only makes sense if "Captain America" is a superhero name known around the world. Which raises a question with, as we see it, two possible solutions. The Justice League world in which Shazam! is set unofficially includes Marvel heroes fighting their own battles away from the likes of Batman, Superman, Wonder Woman, and Aquaman. Or Captain America, the Avengers, and the rest of the MCU is simply their real, comic book selves being read by superhero enthusiasts.
Since there are sure to be some MCU fans who will call the move petty on DC's part, there is an argument to be made that it was Captain Marvel which first passed on the chance to pay respect to Carol's predecessor. After all, Billy Batson first appeared as "Captain Marvel" all the way back in Whiz Comics #2, released in 1939 less than two years after Superman kicked off the superhero genre. Marvel's version of the hero--the original, Mar-Vell--didn't appear until 1967, and Carol Danvers one issue later.
Still, it would have been nice if Freddy referred to Billy as "Zap-tain Marvel" to throw the fans a wink. But even if star Zachary Levi supports Captain Marvel, it's not hard to see why Warner Bros. would choose against free advertising for the competition. Fans will just have to be satisfied with the actual comics, where it's been hinted that Captain Marvel and Shazam are the same hero, just set in two parallel universes.