Why do steel string, so called folk, guitars have cambered (radiused) fret boards? Why is the nut width of steel string guitars typically narrower than the 51-52mm standard for classical guitars?
Is the design of the folk guitar the product of evolution to a more efficient mechanism?, or is it because influential builders like C.F. Martin, a cabinet maker, learn much of his guitar building from Johann Stauffer, a person known as a violin and cello maker?
Does anyone know when these innovations (including the common use of steel strings) caused a branching of guitar design and construction, or of sources that may provide the answers to these questions?
And, would anyone care to argue the merits of one design versus the other?