I am certain that someone will point out to me an example of a high-value industrial work that was allowed to fall into decrepitude and neglect
Ok, since no one else has to date, I will. My example is the Longford Gas Plant, one of the largest and most profitable in the world. It processed pretty much the entire gas oitput of Australia's richest oil province, and supplied virtually all the gas and LPG needs of the city of Melbourne. The revenues generated by the plant were several million dollars PER DAY. Still, the American bungee-management decided to save costs by cutting maintenance "'till it hurts".
Then this happened: http://en.wikipedia.org/wiki/Esso_Longford_gas_explosion
I worked at Longford in 1999-2000, on a backlog of modifications and maintenance requests, some dating back to 1979. Documentation decay was well and truly happening. One example that comes to mind is that certain drawings of underground piping, carrying gas and LPG, were lost. Excavations were a bit of a problem...
Here's an account by a retired engineer of what happened when his old company wanted to streamline a process in the factory where he used to work.
People only knew how to keep the factory going from one day to the next, but all the documentation was lost-- the factory had been sold a couple of times, and efforts at digitization caused more to get lost. Even the name of the factory had been lost.
Fortunately, engineers keep more documentation than their bosses allow them to. (Trade secrets!) And they don't throw the documentation away just because they've retired.
I've been concerned about infrastructure neglect for a while, and this makes me more concerned. On the other hand, instead of just viewing with alarm, I'd like to view with quantified alarm, and I don't have the foggiest on how to quantify the risks.
Also, some of the information loss is a result of a search for efficiency. How can you tell when you're leaving something important out?