Well, Discord purports that Twilight put *all of the world's* magic in the crystals in the comics. However, he does go on to say that as long as the crystals were protected and ponykind lived in harmony, magic would be kept alive and well in Equestria. So magic disappearing was not Twilight's fault, I am aware, I was just stating what she did with putting the magic in the crystals.
That DA post should be given an update though, because yeah, I did just catch some things that should be reworded.