Not necessarily. Public domain and fair use don't require distribution to
occur. Ex: Photos taken in the 1890s are public domain, and you may know that they exist (having seen a print in a no-photography-allowed museum), but the owner of the only copy of the photo is under no obligation to distribute them.
If fair use tells us that it's ok to use parts of copyrighted works for certain purposes, then there must be a legal avenue for obtaining those parts.