With more than forty-five years in the museum field as a curator, director, consultant, museum studies educator, writer, and trustee, I have noticed that, in spite of a professed concern for the preservation of their collections, and in spite of the shock expressed when collections are lost to disastrous human or natural actions, museums are more than willing to engage in purposeful destruction of their collections.
Museums consciously trash things expected to be held in perpetuity for the public good by deaccessioning items without requiring preservation caveats of the next owner. This largely happens when museums sell items on the open market. To be sure, the vast majority of museum collections are secure for the moment. But as more and more institutions are overwhelmed by their expanding collections, and the cost of maintaining those collections, museum holdings will contract.