Because of the legal contracts signed before Disney were on the scene, that Marvel made to stop them going bankrupt.
Marvel Studios will not risk getting sued.
We haven't seen that at all.As a way to get around it, they're making Scarlet Witch and Quicksilver Inhumans in Avengers.
We have seen already that the Terigan Mist or whatever - has restored mutant powers to MANY mutants who lost their powers thanks to Scarlet Witch's "No More Mutants."
The Phoenix Force and Hope Summers un-did Scarlett Witch's hex at the end of AvX.
The Terrigan Mist had absolutely nothing to do with it.
All the Terrigan bomb did, at the end of Infinity a year after AvX & a year after new mutants, was re-awaken the hidden Inhumans.
And they're not making them Inhumans in the films as far as we know so far - they were clearly called 'Miracles'
Yes it's a complete stretch in the Marvel mythology.Is it a far stretch to say - the mist restored these powers - because they were mutants? And those humans, who have recently gained powers, did so because they had the "X" factor in their genes (let's not call it the Mutant Gene). And the Mist simply awakened their powers.
It really is though.And thus, couldn't we logically say, that all "mutants" are indeed Inhumans?
Is that such a far leap?
It's the IP and branded trademark of the character/series that's the problem; not the word mutant. The word mutant isn't copyrighted. There are varying films with mutant in the title and there still can be.
The mutant gene isn't the problem it's the trademarked character names under the X-Men umbrella.
The agreement between Disney and Fox for Scarlett Witch & Quicksilver so that both companies and universes can freely use the characters is that they're not referred to as mutants in MCU films so as not to cash in on each other's films - a fair compromise and one that certainly doesn't stop X-Men comics being created.