I can pretty clearly remember hearing about the "3-2-1 backup rule" by name 10 or 15 years ago on the Security Now podcast with Steve Gibson. So it is _at least_ that old, but probably even older. The concept of having multiple backups is not at all new, however. Since I've been involved with computers (~30 years), I have heard folks say things like "two is one, one is none" in reference to backups and data replication in general.

Also, this TV station has not been sending their show archives to Iron Mountain for the past 70 years. Probably what happened was: In 2019, they had an on-site or nearby archive. Then some enterprising IT director came along and convinced management that they would save a bunch of money and time by outsourcing everything to a third party who said they could do it for cheap. Very confident in their genius, they then scrapped their own archive entirely.

Part of me pities them for ending up in this situation, the other part of me believes they got everything they asked for.