The only reason why man of steel did so well at the box office is because the film has the Nolan name stamped on it
It might shock some folks to learn that over nine out of ten people who go to the movies have no idea who produces, directs or writes a given film. There are only one or two names that are actually well-known to the majority of the general public; Nolan isn't one of them (nor, apropos of nothing, is Whedon or Bay).
The association of certain behind-the-scenes folks with a movie is enough to get the attention of fans and aficionados, which helps to promote a movie - but it's not nearly enough to draw in the audience and make a film a big hit.
Man Of Steel is a better and more accessible movie - and a lot more people give a crap about Superman than Star Trek. It's that simple.