I think part of the problem with Hickory is that people don't know what type of Hickory they are actually getting.
The Bitternut variety is quite brittle and it often seems to be the type actually in lumber form.
Many times I have seen a stack of Hickory that is labelled Shagbark and the few pieces with a chunk of bark remaining on them have all clearly been Bitternut.
The bend test of pieces of it actually fare very poorly and break readily.