Yes, M Ted, regarding "art form".   But the boards of directors, etc were there in 1966 as well as 1967. What changed was a whole bunch of fans--and journalists--suddenly thought they were seeing art in rock.   Hence "art-rock". And more fascination with twisting dials and creating non-human sounds.

My assertion, and I believe, that of the book's author, was that this --taking rock as an "art form"-- started with Sgt. Pepper--and was not good for rock.