Most People who work in Production Operations environments of any scale, discover what has taken Joel the better part of a decade, in the first two-three years of their career.
I almost feel like that Airplane passenger sitting beside Brooks Jr - Brooks saw him reading his book, "Mythical Man Month" - and asked the guy (who had no idea who he was sitting beside) what he thought of the book - The gentleman responded that it was basically a summary of things he knew already. Joel is a giant in the industry, but he does have a tendency to discover/restate the obvious.
"It's not backups, but the restores that matter" - is kind of the mantra of every single person who has ever been responsible for backups.
Then, you go to _any_ class on running a production environment, and you discover things like RPO, RTO, Dress-Rehearsals, etc.. and the whole "It's restores that matter" begins to look quaint.