The biggest problem with maintaining such ancient computer systems is that the original technicians who knew how to configure and maintain them have long since retired or passed away, so no one is left with the knowledge required to fix them if they break.
That’s from this amusing article on ancient computer systems still in use today (how about the company in Texas using punchcards!).
In Asimov’s Foundation series we’re introduced to the idea of technology beyond the understanding of anyone that uses it. Its use spawns a religion around the ‘magic’ it performs. God forbid it breaks!
I’m also reminded of Kevin Kelly’s book on technology:
I told him it would take me a half hour to find a tool, an invention that is no longer being made anywhere by anybody.
Go ahead, he said. Try.
If you listen to our Morning Edition debate, I tried carbon paper (still being made), steam powered car engine parts (still being made), Paleolithic hammers (still being made), 6 pages of agricultural tools from an 1895 Montgomery Ward & Co. Catalogue (every one of them still being made), and to my utter astonishment, I couldn’t find a provable example of an technology that has disappeared completely.