The Marvel Cinematic Universe is doing very well at the moment with everyone chanting the names of the Avengers. I myself being an ardent fan of the MCU am awaiting the next installment Infinity War. Now everyone knows who Superman and Batman is, regardless of age and gender. This was the case for several decades - because DC comics is a much older entity with a more established and older fanbase. So why is a Franchise which is relatively new scoring better at the box office? I suspect it's because of the reasons given below:
1. Marvel is new, fresh, and light hearted.
It's nice to delve into the dark world of DC with Batman every once a while. But the MCU prides itself on churning out more optimistic story arcs with lesser gore and laces it's heavier storylines with humour and hope. I mean who doesn't enjoy a few laughs. DC on the other hand has dry and darker tones of humour with lesser comic relief through characters.
2. Marvel takes its time to flesh out characters.
Each character brought out by MCU has several layers to it. There is a dedicated movie to dive into the motivations behind the characters, what drives them and what makes them tick. They use references which repeat with every movie that comes out. They showcase idiosyncrasies which tie into the movie plot in some way and basically ensure the character is far from 1 Dimensional. DC Comics also tried to breathe life into all aspects of a character, but fails to match the efforts of MCU.
3. Marvel Intertwines, Cross Connects and meshes its Plots and Characters
This is probably one of the biggest reasons for the success of the MCU. Marvel invests significant time to grow their characters and seed connections in other movies and characters so that the audience feels a sense of continuity and familiarity enhanced by fresh details about the same comic characters. This phenomenon can be observed when the audience doesn't move during end credits. They're all waiting for a juicy end credit scene which will connect the next movie or character to what they just saw. That's the reason Infinity War did so well.
Anyone who watched any Marvel Movie went to watch Infinity War since they felt it was linked to their favorite character in some way. This is brilliant marketing to say the least.
To conclude, the MCU is doing better in the theaters just because Marvel movies are fun, fast and completely entertaining. They ensure that the audience has a good time and go home with a sense of redemption and hope.