They put stuff in for the fans, yes, but the movies are mainly directed at general audiences. Otherwise they wouldn't make the money they make.
Could we please finally stop with this "fans vs. general audience" fallacy? It's wrong. It doesn't exist.
Especially the notion that a film "made for" fans is boring for non-fans. Who the fuck came up with this?
And when you've been "part of the general audience", and you become a fan of one film, is the sequel suddenly "not made for you", because you are no longer "part of the general audience"?