Before being banned from the forum, Speakeasy had made it his task to track down these old audio-lingual materials and try to get the publishers to release them into the public domain. Sometimes he was successful, and sometimes he was not.
Generally speaking, these types of situations crop up all the time with old courses. My recent experience with trying to find all the materials for the old 1990's multimedia course for Catalan- "Digui, digui" is illustrative of this. The videos are online, unofficially. The books are available for purchase used. The accompanying audio is not available for purchase as far as I know.
Booksellers who have no knowledge of language-learning most often do not include the accompanying audio or only the books survive to be passed along through the years. Audio formats change from vinyl -> cassette tape -> compact disc -> mp3 -> flac -> whatever is next. Along the way the older formats get discarded.
The same booksellers cannot keep up with every genre of book and know its value on the open market. So, they rely on an algorithm to price their offerings. The algorithm knows that the book is out of print and considers it a collectors item and prices it outrageously as a result. If the bookseller were an individual with whom you could sit down and have a conversation, they would probably come to realize that their is no real collector market for such books and perhaps would lower the price to a reasonable one.
Old language courses from 50 to 60, even 70 years ago can still be used to learn languages. Often times they are more thorough and effective for self-learners than more modern courses and materials. When one wants to get access to older materials that are out of print and no longer for sale, there are most often few options available. Publishers do not want to compete against their own older courses, if they are still in the business of developing and selling new material. This gives active course publishers little incentive to make older materials available easily. Publishers who have since gone out of business or are no longer publishing language courses also have little incentive to cooperate other than altruism. The publishers and copyright heirs can be hard to next to impossible to locate. The appeal to altruism more often than not can fall on deaf ears. Speakeasy would go down the rabbit hole and follow every trail until it dead-ended... which it often did and does. This leaves few legal options for a learner to pursue.
In the US, the Library of Congress keeps a copy of almost everything published. University libraries often have an extensive collection. One legal option is to make a request from your library through an interlibrary loan
for the material with as much identifying information as possible for the materials sought- title; author(s); date published; isbn number if available. If an individual wants to make use of those materials for themselves, there is the fair use doctrine
. In the case of the materials at Cornell University, it may indeed be possible to find them through an interlibrary loan... or not. Sometimes it's better to just give up and find something else.