I also think that CBMs have reached a plateau. One big blockbuster/cbm at the least is going to flop no matter what imo. I liked Shazam a lot and I was stunned to see its numbers.
At the end of the day WB is going to have to be careful about the rating, target audience, release date and marketing in the future. I just saw that next year they have Matrix, Batman, Black Adam, Suicide Squad, Fantastic Beasts and Sherlock Holmes. Then there's Avatar and 4 MCU films, John Wick, the next MI and more. There's just no way all of them will succeed.
Honestly of them all its the WB films that seem most in danger. I think Matrix and Batman will make bank but numbers associated with the other franchises aren't exactly stellar. Even Batman might feel the blow of Snyder's trainwreck.