I've not done a FFL transfer in 20 years, and in my circle of shooters I can't really think of anyone who does not try to buy used (meaning privately) long before dealing with a FFL.
Count me in as one of the people who was astonished by the 40% number being thrown around. I buy several guns every year. Year to year, probably around 4 per year. And I almost never buy them any other way than a transfer to my local FFL. I don't look in the newspaper for guns. Or any other local media. I buy my guns on gunbroker or from the Classified sections of the Ruger and S&W forums. All those get sent to my transfer FFL. (Or I buy C&R guns that ship straight to me.)
Every now and then... some gun friend offers me one of their guns for a good price and I buy it. One happened this year actually. But that can't account for more than 1 in 10 of my guns. So put me in the less than 10% category.