Further, a lot of that old media tied up in proprietary formats that simply don’t exist anymore.
Fuck, half the equipment I used in local television news broadcasting 20 years ago is all up in smoke. Media from that time is on tapes that probably don’t have easily findable tape decks to play them.
I would suspect its similar happens in print media.
In fact, I know it happens in print media because Adobe PageMaker was big for a long time. I used it to build and format my high schools newspaper when I was in my senior year. I was the layout editor because I was the only one who knew how to halfway use it.
Adobe InDesign was the successor to PageMaker and… for a while… you could convert PageMaker documents to InDesign documents, but they dropped that support years ago.
So you want an old Adobe PageMaker file from the 90’s to recreate lost information from then?
Well you better figure out how to pirate both an old copy of Windows and the final version of Adobe PageMaker just to be able to fucking run it in a virtual machine or something. Adobe is fucking ruthless when it comes to copy protection.
End result: Why would a business hold on to documents it functionally cannot use because the proprietary program or hardware used to “read” it no longer functionally exists? They simply won’t the cost of keep useless documents around is too high.