That's the rule, but every so often you get something you don't see too often: a "smart' company. Hewlett-Packard in its day was one of those rarities IMO. I worked with them for a couple of years in the early 90's. This was after its heyday with Bill and Dave at the controls but I still I loved it. They processed and process-controlled everything and the results were sustained quantity. From what I could tell PM was not an issue at HP.
No doubt there’s “wear and tear” after 50 years, and even concrete is not indestructible. But I can’t get out of my mind the sidewall drains that weren’t operating in the area of the failure. That water was going somewhere. Underslab erosion? Slab jacking? No matter, it was an upset condition, and should have been addressed.
The operators knew it, yet took no action. If us novices can see the problem, then those “professionals” who we taxpayers pay to perform should have known.