People who are mad about The Amazing Spider-Man because he can't return back to Marvel Studios need to calm down. It's still possible for Spidey to be in the Marvel Cinematic Universe, it's only a matter of when and how. I mean people love Spider-Man and they also love the MCU or at least The Avengers. If you put both of them together it's a win-win. I'm sure Sony knows this.
Source [http://www.comicbookmovie.com/fansites/Castle/news/?a=63118]Collider's question:
Because The Avengers was so huge, and people now like seeing there superheroes now in one film, is there any sort of plan for studios to combine their efforts and allow Spider-Man to join up with the larger Marvel universe?
Avi Arad's response:
Creatively, it would be a trip, it would be wonderful. We had Avengers in out slate in Marvel six years ago, so it?s really . . . Unfortunately the thing is, at the end of the day our relationship with Disney and Marvel is really wonderful, and it?s a matter of sitting in a room and carving out . . . This is the mother of all superheroes, and I believe after this movie, no one will ask us any questions again because we believe we?ve made something really special. And if Disney and Sony meet and say, ?Let?s do this. ? Because it all comes back to the comics, and usually in the comics we do team-ups, even DC.