The blame falls with Disney.
But how do, we the X-fans, show Disney that this isn't acceptable to crap all over the X-fanbase?
I would partially blame Marvel. Marvel went after the short-term money and licensed out multiple properties before Disney came along. They likely did this for good business reasons which they may be regretting now. Honestly, if we look at this in the long term, this type of see-saw effect has happened before - when X-Men became super popular, Marvel wrote out a bunch of other heroes culminating in the Onslaught event with 5-6 teams featuring X books at one time. Disney would prefer to have the use of characters like Wolverine, Phoenix/Jean & Scott, Professor X, Storm, and Magneto because they equal money. If Disney is involved in not pushing the X-Men, it's because Marvel was too short-sighted. In all fairness to Marvel, hindsight is 20/20 - Disney was not in play at the time and a number of their licensed deals were not that successful before so "Avengers" came as a surprise after a gamble on their part.
You can stop buying other series but I actually think there are some good non-X books so I'm not willing to take that step myself haha. I just hope that at some point the X-Men get a resurgence - I don't think our comic book money compares to the money generated from the movies, unfortunately, so I do not think there is much to be done besides be patient and gnash our teeth.