A word for our times
Agnotology is a term that has been invented to describe "the cultural production of ignorance".
A call for papers explains further:
Examples include the ignorance of cancer hazards caused by the "doubt" peddled by trade associations (Brown and Williamson's "doubt is our product"), the non-transfer of birth control technologies from colonial outposts to imperial centers (by virtue of successive chains of disinterest and suppression), the non-development of certain technologies by virtue of structural apathies or disinterest, impacts of disciplinarity on agnotogenesis, etc.
...The idea is that a great deal of attention has been given to epistemology (the study of how we know), when "how or why we don't know" is often at least as interesting-and remarkably undertheorized by comparison.
Checking out the term, Google took me to a blog, Bloggence, Cunning, Exile, that explains more, (also here).
Another blog provides the example of doctors losing the ability to turn breech births.
An historical example: Towards the end of ancient Egyptian civilisation, it lost the ability to make "proper" mummies. The technology had always been closely guarded, and it must have been during a period of political and military turmoil that a few key people died, and that was that. (Incidentally that's how we come to call them mummies: the Arabic word mumiya was applied to the later "mummies", which were simply coated bodies with bitumen and wrapped.)