See the "Acknowledgements" section of his book -- pp. 299-304. Yes, Norman had written "The Psychology of Everyday Things" prior to joining apple. But in his acknowledgements to this particular book (i.e. "The Design of Everyday Things" p. 301) he very heavily credits his experience at Apple: "I have learned a lot in the years that have passed since the first edition of this book ... The most important experience was at Apple ... I learned about industrial design first from Bob Brunner, then from Jonathan (Joni) Ive. ... Steve Wozniak, by a peculiar quirk, was an Apple employee with me as his boss, ..."

So while Norman wasn't a neophyte when joining Apple, he clearly credits his experience at Apple for having heavily influenced the specific book we are discussing.

Norman certainly doesn't recommend silent failure verbatim. But what I'm saying is that this is the net effect of his recommendations.