Superhero movies are not flopping, dead on arrival capeshit schlock that no one asked for in the first place is flopping. Aquaman made 400 million dollars on a 200 million budget just in December.
The "biopic of a physicist" was made by one of the most recognizable filmmakers in Hollywood and was further propelled forward by a once in a generation hype campaign that will be impossible to repeat, although there's no doubt in my mind that studios will try nonetheless.
Sure, and it's very disappointing in comparison to the first Aquaman. But for being part of a retired cinematic universe and having comparatively little marketing it still performed alright.
I'm just trying to point out that, because a few, even for superhero movie standards, shit films performed badly and Openheimer performed exceptionally, doesn't mean that general audiences are tired of being fed recycled material.