RIGHT??? i'm just over here trying to make things as disgusting as possible. but YES that would make sense as a driving factor (maybe a member or two of the weird cult of corruption ended up merging with the stuff and it was Bad News and also a sign that they needed to seek answers elsewhere?)
i'm also thinking the nation might have been very isolationist even before the collapse? so most of the outside world doesn't really know anything weird is going on until this group appears and is like "haha yeah um it's yeah it's fine but can i see any books you have on the topic of magical corruption? cool awesome thank you"