The House Of M storyline involved the creation of a new reality in which mutants were the majority species, and humans the minority. This reality wasnt a future timeline, but rather the result of reality having been warped by a vastly powerful mutant creature - in the comics, this was the Scarlet Witch, but it may be that her involvement in Marvels Avengers franchise renders her unavailable for Fox to use, as shes not nearly as affiliated with the X-Men as her brother Quicksilver. Its not that important: any reality altering mutant could be coopted by the storyline to have changed things. The new reality sees familiar faces in unfamiliar roles and settings - in the comics storyline, for example, Wolverine is an agent of S.H.I.E.L.D. - and ultimately results in the transformation of reality back to its original form only with the vast majority of the worlds mutants having lost their powers and abilities. That 'no more mutants' moment has ramifications for the X-Men franchise that will stretch years into the future.