By the way, I read this in just one place, but it makes some sense: hormones can only restore a plant's maximum ability to put out new roots. If you managed the parent plant perfectly so that it put out lots of shoots that were ideal candidates for rooting, and you cut them at the perfect time of year and phase of growth for rooting, those cuttings would root as fast without rooting hormones as with.
If that author is right, then the rooting hormones just make up for taking cuttings at the wrong time of growth, or the wrong part of the plant, or for pruning the plant when it was not in an ideal growth phase for producing vigorous, fast-rooting cuttings.
But that author had a million tricks for chopping plants up and burying them "just so", so that they produced ideal cutting material the next
And she might have just had a "thing" against rooting hormones and was boasting about her ability to do without them. Sorry, I don't have the book here so I could give you the title.
Edited to add:
here's a link to Wikipedia: