The writer makes assumptions that are not necessarily true. ex. " the stick of fig wood doesn't "know" that it sits in any material at all. The stick is blind, deaf, and dumb"
"everything non-essential might simply complicate the process and reduce the probability of success" I assume the writers list of no essential items means all items commonly used by the rooting industry. My reply: I think the proper word in this sentence is helps and not complicate.
I'm imagining a possible set-up including (1) a sterilized plastic box, (2) 2-3" of perlite, (3) 1/4" of perched water; (4) a rack, like the ones used to hold test tubes, placed on top of the perlite, (5) cuttings, cleaned with bleach or peroxide, standing upright the rack, (6) a warm location. We could, of course, add a biocide targeting bacteria and/or mold. My reply: The above sentence sounds much like the common rooting process. He writes about rooting only in air (with humidity, oxygen, heat) yet uses is a very common rooting medium (perlite) and rooting process.
Can this be true of citrus? Vlad, you probably have already guessed the answer.
Comment: A major reason for the failure of a cutting not rooting is because the cutting being selected was lacking enough stored energy .