Because my friend is one of them and he lost the interest in the series in XY for this.

I told him than SM is cooming this month and he was like: "dude.i don't care about pokemon anymore unless they make at least 100 new pokemon"

I want to play with him again but i don't think he's going to enjoy a game without a lot of new pokemon ever again,he seems to be tired about the old pokemon overall.