And this is one reason I get ticked off that English departments hire five or seven “Postcolonialists” or “African-American Lit” specialists for every one person who specializes in anything from medieval to Victorian. If there’s no foundation in the canon, there’s no way to fully appreciate or understand what the non-canonical (or new canon) are doing or reacting to.
And I’ll say that I generally like Morrison, often enjoy Erdrich, and love O’Brien and that almost all of my previous research/writing focus has been non-canonical . . . but I have a reasonably strong canonical background (not the best it could be but, perhaps slightly better than average).