Who knows what will happen... it's hard to predict the future sometimes..
Yes, the author was crazy with really outdated views and the fanbase is getting older. However, that shouldn't diminish the historic nature of the book.
Cerebus 1 pretty much marked the new era of independent comic creators. Paved the way for TMNT, Elfquest, Usagi, Grendal, Crow , Spawn so it will always remain relevant in a historical context
Obviously, he won't permeate through popular culture like Archie but the book will likely stand with time. Plus, there are only 273 slabbed copies...