Quote Originally Posted by Devaishwarya View Post
Because it's not really "their story" to tell.
Regardless of the 'shared' universe in which they live...the X-Men have always operated apart. Unless the story requires SHIELD or the Avengers to step in there really is no need for them to show up.

And I'm quite okies with that.
We know the "real" reasons for this, but they need to put some excuse in the books. If not, you have embarrassing moments like Cap saying "we didn't help you because we respected you".