Originally Posted by dr wu
...I have no doubt that those bands themselves would have said that to anyone who asked. Simply because rock itself evolved into various forms which carried along many bands doesn't mean those bands were attempting to be 'progressive' or trying to actually be prog rock artists.
Of course those bands weren't deliberately trying to be "progressive". They were just following the path blazed by their rapidly expanding interests. Had they been self-consciously trying to be progressive, they would have been trying too hard and they would not have recorded the good music that they did.