In the 1960's, record companies would have never dreamed of not attaching a face to a band. They made sure you knew exactly what The Four Seasons, The Beach Boys, and The Beatles looked like. All of The Beatles early album covers were simply photos of the band. It wasn't till The White Album that you didn't see their mugs on the cover (they were on the Magical Mystery Tour cover, but in costume - so this may or may not count). However, even The White Album came with 4 big glossy pictures of John, Paul, George and Ringo.
Somewhere in the mid-70's, record buyers started caring a lot more about the music and a lot less about their faces. Could you pick a single member of Supertramp out of a lineup? Hell no - no one could. They were faceless.
Bands like Chicago, Kansas and King Crimson had been relying on their music rather than looks to move records, and by the time Boston came around in 1976, that was all she wrote. Who gave a damn what Rush or Styx looked like - their tunes were kickin' and that's all that mattered.
It's ironic that punk was a rebellion against this prog and album oriented rock, since punk was supposed to be all about music over image. Yet, that is exactly what bands like Yes and Blue Oyster Cult were - faceless, and just about the music. The Sex Pistols hated Pink Floyd with a passion - but IMHO their hate was misdirected.
When I compare The Sex Pistols to the prog rock band Curved Air (see below), I can understand why Johnny Rotten might be repulsed by these bands.
On the other hand, their looks and wardrobe shouldn't be important if you care about the music. Punk was far more concerned by outward appearances than these prog and AOR bands.
Of course, by the early 1980's both AOR and punk were dead. They were both replaced by a kind of music that openly and unashamedly embraced image over music. Goodbye Foghat. Hello Duran Duran.