When I was 17 I became attracted to Jazz by and for the advanced chops of the musicians (when you’re young, guys who play things which are physically difficult to perform---as opposed to things which sound "good", and/or serve the music---are considered to be better musicians than those who don’t.).
So when Jazz-influenced players appeared in Rock ’n’ Roll in 1967 and 8 (okay, Earl Palmer and Jim Keltner were originally Jazzers, but they didn’t play Rock ’n’ Roll in that style), I initially got into the music they made. I went to The original Fillmore Auditorium to see and hear The Nice, Keith Emerson’s pre-ELP band. That phase of my musical path was short lived, cured by The Band. ;-) Somewhat ironic, as organist Garth Hudson was very Jazz-influenced, loving Bill Evans and other instrument masters of the genre.
But Prog bands, they make music which assumes complicated song structures and hard-to-physically perform instrument parts are ends unto themselves. And the music is made as, it sounds to me, a form of bragging: see how good I/we am/are? At the risk of drawing the ire of perhaps some (or even many) here, I must disclose that I feel the same about the music of Frank Zappa. Sorry. ;-)
