The way I see it frame design is only part of the Retrobike equation. It also has to do with history and provenance.
Guys like Rody honed their craft under the masters and are carrying the mantle into the future. It is a labor of love with these guys. If they are building you a bike they are not going to cut corners or hide something that was not up to snuff. These guys are not just thinking of the paycheck. Each frame they design and build is like a child to them. Nothing is going out the door that they wouldn't feel comfortable and happy riding themselves.
Have you ever been in a shop watching somebody like FTW, CH, CI, SN, TR, et.al. They are so freaking into what they are doing and the material they are working with... it is incredible to see a true craftsman ply his or her trade. And, their medium is not the easiest to work with. It takes time and patience, years of trial and error. They are not only machinist/welder/engineer, they are also true artists.
Plus, these guys are great people that care about the sport, its history, and its future. They don't hesitate to take the time to answer questions and share their insight...
P.S. Rody, will this get me a discount on a fork??