Directories may be online elsewhere. Check Miriam Robbins' site https://sites.google.com/site/onlinedirectorysite/
to see what is online elsewhere. Also check the websites of the local libraries and archives that likely would hold these directories, in case there are some that Robbins does not list.

Use WorldCat to see which repository holds certain directories. It's possible the repository would do an ILL (interlibrary loan). I'm not sure how you would buy them.