As to the challenge of the referral theory, I tend to listen to my own drummer. There are so many resources about marketing “advice” and I often wonder if it isn't best to keep thoughts under my hat. Everyone has a theory and certainly there are books and workshops which can challenge paradigms.
For 30 years my thought about referrals has been: “Don’t worry about it”
Referrals are a symptom. I believe if you are committed, have amazing service, and over the top with your delivery... you get referrals.