Well...one issue was the process itself, the materials just weren't meant to last forever - or rather, they were meant to, but they could not. This is one reason I have been trying to find a service to transfer the film (movies & micro).
Another reason, somewhat associated, is that many people were under the (usually) mistaken notion that the media used was flammable, so tossed it, esp. once the emergency was over. We had a standing order at several companies I worked at to toss any and all film over 5 years of age - X-rays, movies, what ever (of course, the X-rays weren't tossed, there was silver on them).
Yet another reason is change of management and/or mergers. Many railroads went through a change of management and direction in the 60s. You had some that stayed true to the corporate heritage (for good or ill), others that wanted "all that old crap OUT!!" With mergers, you'd have the actual winners of the merger (NOT always, or even USUALLY, the purchaser) come into the "enemy" camp and toss anything historical from the company that in one way or another, purchased the other. So...you'd have some people from, oh I don't know, say SP come into Denver and station dumpsters down below the windows, and all manner of materials were simply tossed. Same thing happened to the Wabash. Sae thing happened in airline mergers, software mergers, insurance mergers. Vindictiveness and revenge all too often trumps (heh) the past.
And...from a railroad's point of view, retaining history of rail cars is not seen as a smart move. Why? We'll never use those again. The only one who wants them are nerdy researchers and LAWYERS. Don't believe me? Look at the asbestos lawsuits. We have lawyers calling at least once a month to get data on 80 year old rail cars, because there might be a dime in it for them. Why take the chance? What's that insulation material in that tank car? No...you really don't want a record of that around. And who wants to separate wheat from chaff at that point? Throw it ALL out. Company records could be even worse. Past legal issues get re-fought all the time.
Then there was simply cleaning. A new manager would come into some department, say "get rid of that s**t!!" He was given the job to glean up and garner space. And they did it.
Microfilm can be brittle, poorly packaged, poorly stored, stored incorrectly, etc. And...one off its beneficial attributes became its biggest detriment. Stuff smaller than a fist, is easy to lose, steal, throw out, over look, hide, "store (see hide)", etc. Even in archives. Even in well run archives.
At 06:25 PM 3/30/2020, Tony Thompson wrote:
This topic reminds me of something that came to light when I was researching the PFE book and interviewing retirees. Several told me the same story: that at the beginning of World War II, the government urged western companies to microfilm critical records and store them remotely. The motivation being the possibility of Japanese incendiary attacks on the West Coast. Both SP and PFE did microfilm a lot of documents, specifically including car and locomotive drawings.