I went back to the book to see if I got the facts right.
It acknowledges that use of the technique, referred to as
"double digging", amounts to a formidable job. It states
that it "is the classic technique for creating raised beds".
It has been in use for 5,000 years. The book is not dogmatic
about this, and it approves of other soil preparation
techniques (but it still leaves you with a feeling that
double-digging is the "right" way).

The book is The Complete Vegetable and Herb Gardener: A Guide
to Growing Your Garden Organically, by Karan Davis Cutler.