I realize that a band like Led Zeppelin are not 'prog rock' in the traditional sense, but to me Zeppelin hella lot more adventurous than a lot of the bands that we distinctly label as 'prog'. In many ways, LZ achieved their progressiveness in an un-conscious manner, and in so doing created much more artistic works than those bands that wore their progginess/artsiness on their sleeves. Take two Zep albums that got relatively low scores on progarchives review forum:
Led Zeppelin III: 3.86
Houses of the Holy: 3.69
Compare that to the cumulative review scores for the 2 Transatlantic albums:
Transatlantic Stolt Morse Portnoy Trewavas: 4.09
Bridge Across Forever: 4.05
When I saw these scores, I'm thinking C'MON NO WAY
Houses of the Holy is more progressive, artsy and eclectic than the 2 TA albums combined. Funk, reggae, folk, the subtle time changes, the sounds that Jimmy gets from his guitars and OOOHH that mellotron! No Quarter and The Rain Song by themselves make a lot of neo-prog bands sound trite and contrived. Not to mention the wonderfully organic structures that we get with The Ocean, The Song Remains the Same, and Over the Hills and Far Away. Musically, Page/ Plant/ Bonham/ Jones were exploratory and progressive in every way imaginable. Well, I can't complain too much.... at least they're down as "prog-related"